[[WMG:[[center:[-''[[Series/DoctorWho Doctor Who]]'' [[Recap/DoctorWho recap index]]\\
'''Tenth Doctor Era'''\\
'''Series 2:''' [[Recap/DoctorWho2005CSTheChristmasInvasion CS]] | '''1''' | [[Recap/DoctorWhoS28E2ToothAndClaw 2]] | [[Recap/DoctorWhoS28E3SchoolReunion 3]] | [[Recap/DoctorWhoS28E4TheGirlInTheFireplace 4]] | [[Recap/DoctorWhoS28E5RiseOfTheCybermen 5]] | [[Recap/DoctorWhoS28E6TheAgeOfSteel 6]] | [[Recap/DoctorWhoS28E7TheIdiotsLantern 7]] | [[Recap/DoctorWhoS28E8TheImpossiblePlanet 8]] | [[Recap/DoctorWhoS28E9TheSatanPit 9]] | [[Recap/DoctorWhoS28E10LoveAndMonsters 10]] | [[Recap/DoctorWhoS28E11FearHer 11]] | [[Recap/DoctorWhoS28E12ArmyOfGhosts 12]] | [[Recap/DoctorWhoS28E13Doomsday 13]]\\
'''[[Recap/DoctorWhoS27E1Rose <<< Series 1]]''' | '''[[Recap/DoctorWho2006CSTheRunawayBride Series 3 >>>]]''']]-]]]
!New Earth
[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/nunnursecat_4441.jpg]]
[[caption-width-right:350:Quick, throw some yarn!]]
->Written by Creator/RussellTDavies\\
Directed by James Hawes\\
'''Production code:''' 2.1\\
'''Air date:''' 15 April 2006

->''"The Sisterhood are up to something. Remember that Old Earth saying? Never trust a nun, never trust a nurse, and ''never'' trust a cat."''
-->-- '''Cassandra'''

JustForFun/{{The one w|ith}}here the Doctor fondles himself. [[GrandTheftMe Sorta]].
----

The Tenth Doctor, mostly recovered from his regeneration trauma, heads off for more adventures! He takes Rose to visit [[OverlyLongName New New New New New New New New New New New New New New New New New]] York, not only to continue showing her the universe but also because he got a message from there on his psychic paper. Rose is enjoying her bouncy, chatty "New New Doctor".

The message leads the Doctor to a hospital run by cat nuns, but that's not even the strange part. There's a guy who's turning into stone, but even ''that'' isn't the strange part. Among all the [[CatFolk cat women]] and the people TakenForGranite, what's peculiar is that the hospital is too far ahead of its time: they have cures for diseases that haven't been cured yet.

The Doctor is on the case! In the ward, he and Rose meet the apparently dying [[Recap/DoctorWhoS27E2TheEndOfTheWorld Face of Boe]], the oldest being in the galaxy. The Face is dying of old age, which is the only thing the cats cannot cure. Novice Hame, the Face's nurse, tells the Doctor about a legend that the Face of Boe, just before he dies, will tell his last secret to someone like him — "the man without a home, the Lonely God."

Rose, meanwhile, runs into Lady Cassandra ([[Recap/DoctorWhoS27E2TheEndOfTheWorld Remember her?]]), who wants her body. [[GrandTheftMe Literally.]] Using a psychograft, she snatches Rose's body and mind, and quickly realizes that a) Rose likes the Doctor! b) the Doctor ''is'' [[TheNthDoctor the Doctor!]] c) the Doctor is hot! d) a good old-fashioned makeout session is called for, and e) [[ArsonMurderAndJaywalking Rose is a chav!]] The Doctor doesn't mind at all.

So the Doctor and a Cassandra-possessed Rose stumble upon the source of the cats' medicines — a secret colony of artificially grown people, who are held prisoner and infected with everything in order to manufacture cures for everything. The clone-people get out, the Doctor figures out that Rose is not quite herself, and Cassandra is forced to switch back and forth between the bodies of the Doctor and Rose during the ensuing chase. While Creator/DavidTennant camps it up as Cassandra (and Creator/BilliePiper tries ''very'' hard to keep a straight face), Cassandra at one point ends up in the body and mind of one of the sick, and is [[VillainousBSOD severely shocked]] to realize what it's like to ''really'' suffer.

The Doctor gets baptized by the nuns with a panacea cocktail and, with a touch, disinfects the clone-people in a scene that would make Jesus Christ himself jealous. It's [[Recap/DoctorWhoS29E3Gridlock not the last time]] the Doctor will be a MessianicArchetype on this specific planet. Cassandra goes into the body of her dying servant, where she finally dies in her own arms through a bit of foreshadowed time-travel. The Face of Boe, meanwhile, decides that he could stick around for a bit longer after all, and promises to [[Recap/DoctorWhoS29E3Gridlock get back to the Doctor later]] on that [[Recap/DoctorWhoS29E11Utopia big-important-secret]]-to-be-imparted-to-the-Doctor-at-the-time-of-the-Face's-death thing.

----
!!Tropes:

* AbsoluteXenophobe: Lady Cassandra once again sees herself as the only "pure" human and thinks of everyone else as "mutant stock", although this racist side of her gets somewhat subverted this time around. On the one hand, she possesses Rose's body because she fits the bill with regards to her youth, beauty and "pure-blood" humanity, and her discovery of the specially-grown infected humans in Intensive Care gives her just another excuse to proclaim herself "The Last Human". On the other, her dynamic throughout the episode with her clone servant Chip shows that she [[PetTheDog does value his loyalty]], despite initially dismissing him as "not even a proper life-form", thus introducing a [[BenevolentBoss softer side of her]].
* AccidentalSuicide: Averted, the psychograft causes Cassandra's skin to dry out again and her [[BrainInAJar Brain In A Jar]] to give in, causing her old self to essentially "die". But as Cassandra/Rose points out, it also caused her personality to survive by being turned into particles in the air much like a spirit, allowing her to [[GrandTheftMe take over Rose's body.]]
* AlasPoorVillain: Despite her having soared over the [[invoked]]MoralEventHorizon long before she even appeared, Cassandra gets a surprisingly well-written death scene. Becomes an actual TearJerker when you realize the FridgeBrilliance behind it: when her older self expired before her in Chip's body, she was the only person trying to save him/her (though some ''did'' walk off, presumably to get help while everyone else stood around apathetically), shouting for people to try and help... only for people to back away from her and not do anything. Not only did this tarnish her reputation as an upper-class lady (nobody ''ever'' called her beautiful again after Chip), but it was the start of her conviction that people could only rely on themselves. She finally realizes that she was wrong about this when the Doctor commends her on helping cure the artificially created humans, and it's this which helps her accept her long-delayed death. Not to mention that despite her snobbery, she never did forget that Chip's face was that of the last person to ever compliment her.
* AlienSky: New Earth has two moons.
* AndIMustScream: The Sisters of Plenitude believe that most of the clones they keep beneath the hospital aren't conscious (and incinerate those who show any signs of awareness), but in truth, they're completely aware of their situation, constantly suffering from the pain of being infected with every disease in the galaxy while being locked in a tiny cell their whole life, where they can only long for the sensation of human touch. Thankfully, they're freed and cured of their illnesses by the end of the episode.
* AnkleDrag: Matron Casp tries to do this to Rose, blaming her for ruining the Sisterhood's reputation. She ends up falling from the ladder herself when one of the plague-carriers touches her foot and infects her.
* AntiHero: Lady Cassandra, who eventually becomes the [[VillainProtagonist focus of the story]] through her possession of Rose. She starts out as a nasty FemmeFatale seeking to [[EvilVsEvil uncover the secrets of the hospital for her own ends]]. By the end, however, she redeems herself somewhat by helping the Doctor save the day and [[JerkWithAHeartOfGold gaining a fresh perspective on life]].
* AppearanceAngst: [[IAmNotPretty No psychograft or amount of surgery can take away Cassandra's self-loathing]]. After possessing Rose, her first reaction upon seeing her new reflection is one of horror: "Oh my ''god''! I'm a ''chav''!" While it's later made clear that she enjoys Rose's stolen body, [[DistractedByMyOwnSexy grudgingly admiring her beauty and complimenting the more sexual aspects of her appearance]], Cassandra's also nitpicking it within seconds, lamenting on going [[RichesToRags "from class to brass"]], considering more surgical operations, and later planning to replace her host with someone ''younger'' and "less common".
* ArchEnemy: This episode further establishes how Rose and Cassandra are each other's worst enemies, with even a lot of British class-warfare subtext being implied between the two. Cassandra in particular holds a huge grudge towards Rose and the Doctor after her defeat on Platform One.
* ArtisticLicenceBiology: The Doctor discovers an underground lair full of cloned humans infected with, in his words, ''"EVERY DISEASE IN THE GALAXY."'' They don't die since all the diseases keep each other in equilibrium, but if they touch ''you'', you die instantly and painfully. How does the Doctor cure these poor souls? Why, he douses himself in ten or so ''intravenous'' solutions designed to cure the diseases, then transmits the cure by touch. One of these diseases, called "petrifold regression", [[TakenForGranite turns you into stone]].
* ArtisticLicencePhysics: The Doctor's makeshift winch that he uses in the lift shaft is a small traction winch from the Duke of Manhattan's sickbed that can apparently support the weight of ''two people'' plunging dozens of levels downward. During the descent, the velocity and friction cause sparks to fly from the winch itself, but the Doctor's legs are ''grasping the cable'' and yet his trousers don't burn.
* AudibleSharpness: Matron Casp unsheathes her claws with a loud "''sching!''"
* BackFromTheDead: Cassandra, whose improbable resurrection from her explosive demise on Platform One is explained away as Chip having salvaged her brain and eyes "from the bin" and rebuilt her flattened form using skin from her posterior, much to Rose's amusement.
* BatheHerAndBringHerToMe: Downplayed, but the automatic elevator shower is as good an excuse as any for Cassandra to make sure Rose is all "cleaned up" before she has Chip lead her to her dungeon in order [[GrandTheftMe to possess her]]. After all, if Rose is to become Cassandra's new host, she has to be clean for a [[RichBitch high-class lady like her]] to [[DirtyOldWoman dirtily enjoy her sexuality]].
* BattleaxeNurse: Matron Casp, the cat nun in charge of the Sisters of Plenitude.
* BeautyIsBest: Cassandra seems to fall for this as part of her materialist view on life. Despite her classist hatred towards Rose, she praises her new looks several times, proving that she values beauty over everything else; even continuing to call herself [[LastOfHerKind "The Last Human"]] while possessing her. Notable too in that [[VillainRespect Rose is the only person]] who Cassandra recognizes as a [[TheSocialDarwinist "pure-blooded"]] human just like her.
* BeCarefulWhatYouWishFor: Escaping the diseased patients, the Doctor takes advantage of a lull in the chase to threaten Cassandra into leaving Rose's body. "You asked for it," she tells him, and obliges...by transferring herself right into the Doctor.
* BelligerentSexualTension: Despite her murderous intentions, Cassandra has tons of this with both the Doctor and Rose, mostly due to her being sexually repressed for so long until meeting the Doctor in a young body and her own (self) appreciation of Rose's body.
* BenevolentBoss: For all her supremacist delusions of grandeur, Cassandra is shown to value Chip's loyalty, being willing to allow some of his more perverted approaches such as caressing her skin and watching her [[ShamelessFanserviceGirl flaunt Rose's body in front of the mirror]].
* BerserkButton: The Doctor, twice:
** He's absolutely livid at the way the Sisterhood uses its clones (i.e. living things) as essentially husks for diseases.
** He's not too happy about Cassandra's GrandTheftMe of Rose, quite convinced she should accept her time is over. When left with the problem of her finding a ''willing'' host, he still pleads her to see reason, exclaiming [[AndIMustScream such a fate]] just plain isn't fair.
* BestServedCold: Cassandra blames Rose for [[Recap/DoctorWhoS27E2TheEndOfTheWorld her initial demise on Platform One more than two decades ago]] and believes their reunion to be predestined. A big part of her [[GrandTheftMe snatching Rose's body]] and [[PowerPerversionPotential commandeering it for her own personal use]] is motivated by her belated desire for revenge. When she learns the Doctor is also still around, she [[FemmeFatale impersonates Rose to fool him for a while]] and uncover the secrets of the hospital, but plans to kill him later on. Knocking him out and [[LockedInAFreezer leaving him to die in a stasis pod about to be flooded with disease]] would seem to be a fitting end...
-->'''Rose/Cassandra:''' Over the years, I've thought of a ''thousand'' ways to kill you, Doctor...and now that's exactly what I've got: ''one thousand diseases''.
* BettyAndVeronica: The episode's body-swap subplot kind of becomes a love triangle of this type, all for the [[PlayedForLaughs sake of comedy]]. Cassandra would be the haughty "Veronica" to Rose's ordinary "Betty".
* BigBad: Matron Casp.
* BigBreastPride: Cassandra is mortified at the idea of living on through Rose, but it's clear from her "bouncy castle" scene that she's also quite thrilled by the prospect of having breasts again. Before long, she's popped open the buttons of Rose's top and [[ProudBeauty proudly exploiting her new assets to their best advantage]], including as a hiding place. Even though Rose has pockets for her mobile phone, Cassandra prefers to keep her special knock-out perfume close to her chest -- [[VictoriasSecretCompartment quite literally]].
* BittersweetEnding: The Doctor saves the day and the plague-carriers are cured, the surviving cat nuns are arrested by the NNYPD, the Face of Boe is expected to die but doesn't and promises the Doctor they'll meet again, Rose is finally restored to her own body when Chip offers himself up as a willing substitute for Cassandra... Only, Chip's half-life body means Cassandra has well and truly condemned herself at last. The Doctor and Rose taking her back in time to tell her past self she's beautiful is treated as a final kindness, yet Cassandra dies in the arms of the only person she ever truly cared about: ''herself''.
* {{Blackmail}}: Attempted by Rose/Cassandra against Matron Casp: "Give me your donations or I'll tell everyone about your human-sized petri dishes."
* BlasphemousBoast:
-->'''Novice Hame:''' And who are you, to decide that?\\
'''The Doctor:''' I'm the Doctor. If you don't like it, if you want to take it to a higher authority, there isn't one. It ''stops'' with me!
* BodySnatcher: Cassandra's EvilPlan is to use a psychografting machine to take over Rose's body, intending to live on by using it as a replacement for her dying one.
* BodySurf: Cassandra spends the episode doing this, possessing Rose, the Doctor, a clone and finally Chip.
* BodyHorror: Cassandra as usual. Her skin and frame seem even more corroded this time around as a reflection of her determination to survive even if she continues to degenerate. Averted [[MsFanservice once she possesses Rose]].
* BoundAndGagged: Sort of. Functioning as the preliminary stage of Cassandra's [[GrandTheftMe psychograft]] trap, a pair of [[SupernormalBindings self-activating energy filaments]] bind Rose's arms in place like ropes so that Cassandra can complete the transfer inside her body.
* BrainInAJar: How Cassandra survived her apparent death at the end of her previous appearance; her skin may have torn itself apart, but her brain remained intact, meaning that her mind survived just fine, apart from being left ''severely'' pissed-off at the Doctor and Rose.
* BuxomBeautyStandard: Cassandra seems to respect a good chest in another woman and part of the reason why she starts feeling delightful after possessing Rose is because she notices her decent front.
* BringHimToMe: After spying Rose on the planet's surface, Cassandra has Chip override the lift controls to divert her down to the basement. He then lures Rose to his mistress's hideaway under the pretense that he's a member of staff leading her to Ward 26.
* CallAHumanAMeatbag: The Doctor gently chides Rose for staring at the cat nuns, saying to them she looks "pink and yellow". Rose appears visibly stung by this.
* CampGay: Cassandra in Chip's body has the mannerisms, and Cassandra in the Doctor's body arguably more so. Chip, even when unpossessed, has a lisp and spring to his step.
* CatFolk: The Sisterhood are all humanoid cats.
* TheCavalryArrivesLate: It's evening when the NNYPD finally shows up at the hospital to lift the quarantine and arrest the surviving cat nuns.
* CharacterCatchphrase:
** Cassandra's trademark [[Recap/DoctorWhoS27E2TheEndOfTheWorld "Moisturise me!"]] makes a return. It's also the first thing she utters after psychografting herself inside Rose ([[VerbalTic more out of habit than anything else]]), indicating the transfer was successful.
** This episode also marks the genesis of the Tenth Doctor's "I'm sorry... I'm so sorry..." line, first spoken in regret when he and Cassandra witness the horrific diseased state of the Sisterhood's human test subjects. He'll go on to say it [[Recap/DoctorWhoS28E6TheAgeOfSteel many]], [[Recap/DoctorWhoS28E8TheImpossiblePlanet many]], [[Recap/DoctorWhoS28E12ArmyOfGhosts many]], [[Recap/DoctorWhoS29E13LastOfTheTimeLords many]], [[Recap/DoctorWhoS30E5ThePoisonSky many]], [[Recap/DoctorWhoS30E8SilenceInTheLibrary many]], [[Recap/DoctorWhoS30E14TheNextDoctor many]] more times.
* ChekhovsGun:
** The awkward decontamination lifts, best described as a human car wash, make a good dispersal system for the Doctor's cure cocktail.
** Cassandra's seemingly innocuous bottle of "perfume", which she requests from Chip and [[VictoriasSecretCompartment conceals down Rose's cleavage]] before going to meet up with the Doctor. When her cover is blown, out comes the perfume... which turns out to be [[KnockoutGas some kind of narcotic spray]] that she uses to [[InstantSedation instantly knock the Doctor unconscious]].
** The Duke of Manhattan's sickbed has a traction system operated remotely by his assistant Frau Clovis to winch him up and down. When the quarantine immobilises the hospital lifts, the Doctor later uses the same winch as a makeshift pulley which he attaches to the lift cable so he and Rose/Cassandra can [[BigDamnHeroes dramatically]] [[FastRoping slide down the elevator shaft at dizzying speed]].
* ClonesArePeopleToo: The Doctor is ''furious'' at the way the Sisterhood treats the clone-people. He sees them as just as alive as himself or Rose.
* BritishEnglish/CockneyRhymingSlang: Oh sure, Cassandra's killed a lot of people, but she absolutely ''murders'' the art of Cockney when trying to imitate Rose's London accent. Naturally, she trots out all the classics: "Wotcha", "guv'nor", "apples and pears", "boat race", and "I can't Adam and Eve it".
* CompartmentShot: The scene where Matron Casp and Sister Jatt first visit Intensive Care to inspect a conscious "patient" is primarily shot from inside one of the PeopleJars, conveying the infected person's [[POVCam POV]] while keeping his true nature hidden from the audience (only his diseased hands are seen, and we briefly hear his pleading voice).
* ContrastMontage: The lift sequence in which the Doctor and Rose each go through the hospital's disinfectant process, {{Played For Laughs}}. The Doctor treats it as a relaxing shower, while Rose shrieks in shock and smacks the walls frantically.
* CopycatMockery: Invoked by Cassandra in the Doctor's body as she and Rose climb up the maintenance ladder:
-->'''Rose''': If you get out of the Doctor's body, he can think of something!\\
'''Doctor/Cassandra''' [''childishly imitating Rose'']: Yap, yap, yap... god, it was tedious inside your head. Hormone City!
* CovertPervert: Downplayed, but Chip's adoring worship of his mistress comes off as a bit...unhealthy at times, even for a servile half-life clone:
** Cassandra mentions he "sees to [her] physical needs", which [[DoubleEntendre Rose hopes means food]].
** When Chip explains to Rose how he rescued and nursed his mistress back to health, he emphasizes "her ''pretty'' blue eyes" and describes how medicine "soothes her...''strokes her''...", lovingly caressing Cassandra's skin before Rose cuts him off and says she gets the point.
** Not to mention once Cassandra is actually inside Rose's body: Chip spends a whole scene watching with obvious interest as his mistress explores and enjoys her newfound sexuality in the mirror...especially when she removes an outer layer of clothing and stashes a perfume vial down Rose's bra ''right in front of him''.
* ColourCodedCharacters: Rose wears a [[TrueBlueFemininity blue jacket]] for the first third of the episode. When she's possessed by Cassandra, she discards it in favour of a [[GracefulLadiesLikePurple more opulent purple blouse]] which she wears for the rest of the story, symbolizing her shift in personality to the audience and the two characters' [[LightFeminineAndDarkFeminine radically different ideals of femininity]].
* ContinuityNod:
** At the beginning, the TARDIS is parked on the (faded) giant chalk [[ArcWords "Bad Wolf"]] graffito from "[[Recap/DoctorWhoS27E13ThePartingOfTheWays The Parting of the Ways]]".
** As she says her goodbyes to her mother, Rose mentions her cousin Mo from the Peak District, previously name-checked in "[[Recap/DoctorWho2005CSTheChristmasInvasion The Christmas Invasion]]".
** The Doctor mentions Platform One, [[Recap/DoctorWhoS27E2TheEndOfTheWorld where he and the Face of Boe first met]], and Rose's original reference to Cassandra being a "trampoline" is repeated, this time by Cassandra herself.
** The Doctor previously met a form of cat people in [[Recap/DoctorWhoS26E4Survival "Survival"]].
** Rose's Nokia [[SupernaturalPhone "Superphone"]], which the Doctor first upgraded in [[Recap/DoctorWhoS27E2TheEndOfTheWorld "The End of the World"]], makes a reappearance here when the Doctor calls to check on her whereabouts, oblivious that she's presently possessed by Cassandra. Chip recognizes it as "a primitive communications device".
* CreepyBasement: Cassandra's dungeon lair where she's been hiding out beneath the hospital, though for a change it's got white walls and rather more natural light than one would expect.
* CultOfPersonality: Lady Cassandra seems to have this type of control over Chip, who "worships" her as his mistress.
* CurseCutShort:
** To begin:
--->'''Cassandra:''' At last, I can be revenged on that little–\\
''[cut to Rose and the Doctor]''\\
'''Rose:''' Bit rich, coming from you.
** Similarly:
--->'''Cassandra:''' That piece of skin was taken from the front of my body. This piece is the back.\\
'''Rose:''' ''[laughing]'' Right, so you're talking out your–\\
'''Cassandra:''' ''Ask. Not.''
* CurvesInAllTheRightPlaces: Rose (at least according to Cassandra), after she unzips her jacket and realizes her new self is [[BigBreastPride rather well-endowed]]. Suddenly, [[RichesToRags being a chav]] doesn't [[BeautyIsBest bother her all that much anymore]]...
* DeadpanSnarker: Rose/Cassandra, right after she and the Doctor make [[FastRoping a death-defying plunge down a lift shaft]] at breakneck speed:
-->'''Rose/Cassandra:''' Well, that's one way to lose weight.
* DeathOfPersonality: The Doctor mentions Cassandra is "compressing Rose to death", suggesting this is what eventually happens to the personality of the target host of the psychograft, leaving them an [[EmptyShell Empty Shell]].
* DecontaminationChamber: Set up as a ChekhovsGun, and used in the climax to disinfect all the test subjects of their illnesses.
* DefrostingIceQueen: Cassandra slowly mellows out throughout the episode. Unlike her previous appearance, in which she played a somewhat [[ClassicVillain serious role]], we are at first shown through Chip that despite her racism she values the people that remain loyal to her, even allowing some of Chip's perverted approaches and [[CultOfPersonality worship to her persona]]. After possessing Rose, she behaves in a far more uninhibited fashion, [[TheTease flirting with the Doctor]] and giving him a great big snog. Some of her new demeanour might be explained by Rose's influence [[FusionDance after possessing her]] since Rose is rather [[FunPersonified carefree herself]], eventually showing empathy for the suffering of the Flesh after possessing one of them and finally accepting them as a new form of life when she saves them with the Doctor. This leads her to realize where her [[HiddenHeartOfGold true value really lies]] and accept her death for good, passing on a part of herself to the future in a much more "humane" fashion.
* DenserAndWackier: The mood of the episode comes off as this when compared to its prequel [[Recap/DoctorWhoS27E2TheEndOfTheWorld "The End of the World"]]. Comedy is a constant theme, despite still being an antagonist, Cassandra has a lot more funny moments and the Doctor manages to save almost everyone.
* DesperatelyCravesAffection: The cloned disease-carriers suffer from this, and it's partly what makes them so dangerous. After being bred and treated as less than cattle by cold-hearted nuns, knowing nothing but containment pods all their lives, they're so desperate to feel the simple touch of another human once they get out that they don't seem to notice their touch is deadly to other people.
* DidntThinkThisThrough: Cassandra knocks the Doctor out and seals him inside one of the PeopleJars meant for the plague-carriers that's about to be flooded with diseases. When the Sisters refuse to meet her blackmail demands, she releases a bunch of the infected subjects by opening an entire row of containers to cover her escape...including the pod she just locked the Doctor in. It's pretty short-sighted of her, especially since the sickly experiments then free ''all'' of their fellows and unleash the zombie rampage that makes up most of the episode's second half.
* DiedInYourArmsTonight: Cassandra, with her younger self.
* DirtyCoward:
** Cassandra abandons Chip to the diseased clones during their escape, though she's willing to FaceDeathWithDignity at the end.
** However protective she might be of her boss, Frau Clovis is willing to order in a private executive squad and break the hospital's quarantine if it means saving her own skin.
* DirtyOldWoman: She might be posh and sophisticated, but it's also been centuries since Cassandra's had [[BrainInAJar a proper body of her own]]. So of course, after stealing Rose's younger, curvier, hormonal one, she wastes no time in groping herself and giving the Doctor [[TheBigDamnKiss a great big smooch]]. It's implied she even thought of doing the dirty deed with the Doctor through Rose no less.
* DisneyVillainDeath: Matron Casp is touched by her own deadly creations and falls down a ''very'' long maintenance shaft.
* DispenseWithThePleasantries: In contrast with her deceptive charade as Rose around the Doctor, Cassandra is rather more blunt about her motives when she faces down the Sisterhood:
-->'''Rose/Cassandra''': Straight to the point, whiskers. I want money.
* DistractedByMyOwnSexy: Happens to Cassandra with both Rose ''and'' the Doctor:
** When she first [[GrandTheftMe steals Rose's body]] down in the basement, she's initially aghast at her appearance but upon noticing [[BuxomBeautyStandard how shapely she is]], spends an extended amount of time [[ShowingOffTheNewBody posing and preening in front of a mirror, unzipping her jacket, bouncing up and down, playing with her hair, marvelling at her own boobs and fondling her "nice rear bumper"]]. She's so taken with her new shape that she barely heeds Chip's warning to beware the Doctor and later pays almost no attention to the Doctor's outrage at the Sisters' breeding farm because she's too busy checking herself out.
** Replayed later on when she leaves Rose to possess the Doctor instead (though with no mirror-gazing this time). They might be trapped by a horde of rampaging disease-carriers, but Cassandra takes the time to note the Doctor's slim and foxy frame and hardly-used "parts"!
* DoesntTrustThoseGuys: Cassandra: "Never trust a nun, never trust a nurse and ''never'' trust a cat." By the way, we're dealing with people who are all three at once. Nun nurse cat-people. Although in that case, they really shouldn't have been trusted...
* DoubleEntendre:
-->'''Cassandra:''' Chip sees to my physical needs.\\
'''Rose:''' Hope that means food.
* EatingTheEyeCandy:
** What Rose has been doing, according to Cassandra. The smile Rose gives when Cassandra accuses her of such confirms it.
--->'''Cassandra/Doctor:''' Ooh, he's slim... and a little bit foxy. You thought so too. I've been inside your head. You've been looking... ''[gets in her face]'' you ''like'' it.
** [[HypocriticalHumor Cassandra herself]]. Five minutes after being dumped into a twenty-year-old woman's body full of hormones, she can't resist grabbing the Doctor for a rather passionate snog, even though she hates the Doctor and wants to kill him nastily.
** The Doctor looks Rose up and down when he calls her "pink and yellow". He also glances at her chest right before Rose/Cassandra kisses him.
* ElevatorFailure: The hospital's lifts stop moving when the Sisters enact a quarantine. This means the Doctor and Rose/Cassandra have to climb up an abandoned service shaft to escape the plague-carriers, and later [[FastRoping zipline down a lift cable]] so the Doctor can mix his medicine cocktail into the disinfectant system.
* EvilBrit: Cassandra, natch. Just like in [[Recap/DoctorWhoS27E2TheEndOfTheWorld "The End of the World"]], her character is used as a parody and deconstruction of the [[TheSocialDarwinist darwinist/capitalist]] and conservative villainess archetype, this time through her possessing Rose to extend her lifespan in spite of her classist hatred towards the latter. Although she's [[ProudBeauty pleased with her new looks]] Cassandra also can't wait to get rid of [[PrincessInRags her new social status and regain her wealth]]. It's later made clear in the episode that a lot of her cynicism wasn't justified, as she realizes that [[RichBitch her materialistic drive to possess everything]], throughout her life was a way of pushing away her true value, discovering [[HiddenHeartOfGold a tender side of herself she previously saw as a "weakness"]]. While Cassandra's eugenicist views were left ambiguous in the past, she is more straightforwardly presented as a [[TheSocialDarwinist British White Supremacist this time around]].
* EvilCounterpart: While they are usually foils to each other, Cassandra is thematically presented as this to Rose in different ways this time:
** When it comes to their role as the Doctor's companion, while Rose plays a certain detective role and has her relationship with the Doctor based on trust, Cassandra also plays a similar role, but is more cunning about her intentions and is the [[FemmeFatale Femme Fatale]] to Rose's loyal companion detective.
** When it comes to their femininity, while Rose is gentle and caring and somewhat shy about her feelings, Cassandra is aloof, sultry and cynical, being more straightforward when it comes to their feelings towards the Doctor.
** Finally, due to Rose becoming [[GrandTheftMe Cassandra's new flesh]], with their personalities [[FusionDance merging to some extent]], Cassandra ends up becoming an [[EnemyWithin evil alter-ego of Rose]], helping portray their contrast.
* EvilCostumeSwitch:
** After taking over Rose's body, Cassandra ditches her jacket and spends the rest of the episode with her purple blouse unbuttoned, [[SensibleHeroesSkimpyVillains showing a lot more cleavage than Rose normally does]]. Though she's clearly pleased with her new looks, she also ponders getting some plastic surgery.
** For her scenes as Cassandra, Creator/BilliePiper wears a darker shade of lipstick and emphasises her figure with a wonderbra.
* EvilGenius: Downplayed, but Cassandra is sly enough to fool Rose into falling for her trap in order to possess her, is shown to possess knowledge about computer systems from the future on par with the Doctor, figures out the secret of the cat nuns minutes after possessing Rose and being able to move on her own and is in essence an [[TheSocialDarwinist evolutionary eugenic conservative]].
* EvilIsHammy: Creator/BilliePiper and Creator/DavidTennant have a grand old time camping it up as Cassandra. In fact, Creator/RussellTDavies says this came about because Billie Piper wanted at least one episode where she got to be funny.
* EvilPlan:
** Averted with the Sisterhood. However unethical and criminal the Doctor finds their human lab-rat operation to be, Novice Hame argues they are acting not out of malignant intent but [[MoralPragmatist practical necessity]]. They genuinely believe their methods are helping people, since humanity's colonization of New Earth brought with it an insurmountable onslaught of new diseases to deal with.
** Having survived her downfall on Platform One, Cassandra sees [[GrandTheftMe hijacking Rose's body]] as the ideal opportunity to enact {{revenge}} on her, restore her youthful beauty and continue on living for centuries inside a body of pure human stock. She impersonates Rose so she and the Doctor can uncover the Sisterhood's secrets, then tries to {{blackmail}} them into giving her a fortune so she can make her escape.
* EvilSoundsDeep: Rose's voice gets significantly deeper after Cassandra's possession, gaining [[EvilBrit her Posh accent too]].
* EvilWineGlass: While it never made it to the final cut, an extended scene of Cassandra-possessed-Rose joining the Doctor in Ward 26 included the servants of the Duke of Manhattan offering them drinks, which would have caused Cassandra to slip out of character and reply [[CharacterCatchphrase "Oh, moisturize me"]], almost exposing her facade. Cassandra was apparently [[TheHedonist fond of high-quality drinks]].
* EvenEvilHasStandards: While Cassandra claims to be willing to "junk [Rose] with the waste" once she finds a more appropriate host, at the same time, Rose is such a [[FantasticRacism rare breed of pure human stock]] in Cassandra's eyes that she is willing to protect her as long as she remains as her host. When she finds one of the Flesh, she gets worried her body could be infected by the diseases.
** She also expresses ''shock'' at learning (after possessing a Flesh) the very scope of how badly neglected these beings have been. This is [[LackOfEmpathy Cassandra]] we're talking about, and even she is devastated by the idea of anybody (even "[[IronicEcho mutant stock]]") going their entire lives without physical contact.
* EvilOldFolks: Cassandra plays this straight at first but it gets averted after she steals Rose's body, becoming physically young again.
* EveryoneLovesBlondes: Cassandra is quite pleased at the idea of becoming a blonde again, later arranging Rose's hair to resemble her original looks. She later spends the rest of the episode [[DistractedByMyOwnSexy marvelling at it and fondling it with care]].
-->'''Cassandra:''' [[EvilIsHammy The Lady's moving on]]. It's goodbye [[FacialHorror trampoline]], and [[MsFanservice hello blondie]]!
* EvolutionaryStasis: Despite being said to have changed, the humans still look human. Or, according to the Doctor, they look human ''again''.
* ExploringTheEvilLair: How Rose finds Cassandra when the lift sends her to the basement instead of Ward 26.
* ExpositoryHairstyleChange: Rose's hair is noticeably shorter from this episode onward, reflecting the more mature, confident woman she's growing into alongside the new Doctor in Series 2.
* {{Fainting}}:
** Rose briefly blacks out after Cassandra first completes the psychograft transfer inside her body. The episode depicts the possession as taking an increasingly [[PossessionBurnout heavy toll on her mind]], and she almost swoons in the Doctor's arms when Cassandra finally vacates her body for Chip's.
** The Doctor immediately passes out on the floor after Cassandra gives him a whiff of her [[KnockOutGas knock-out perfume]] and is unconscious long enough for her to trap him inside one of the Intensive Care PeopleJars.
* FaceDeathWithDignity: Cassandra's last act is to tell her younger self that she is beautiful. Then she dies without a fuss.
* FaceOfAnAngelMindOfADemon: Cassandra's possession of Rose is supposed to invoke this as part of the themes of what makes a person "human". Despite her attractive new appearance and behaviour, Cassandra is still a non-human "monster" even while possessing Rose.
* FacialMarkings: Chip's swirly henna tattoos.
* FakeFirstKiss: The breathless, exuberant snog Rose gives the Doctor in Ward 26. The Doctor is left speechless ([[StillGotIt but also sort of chuffed]]) by such an unexpected outburst of affection from his companion ...except of course, [[NotHerself it isn't really her]].
* FallingIntoHisArms: Rose nearly faints from exhaustion when Cassandra finally leaves her body for Chip, and the Doctor has to catch her. The two of them share [[HeldGaze a joyful little reunion together]] before Chip/Cassandra breaks the moment.
* FanservicePack: Cassandra gets a huge upgrade, going from [[BodyHorror the monster of the show]] to one of the most [[MsFanservice sensual characters in the series]].
* FantasticFlora: "Apple-grass" grows in the green meadows on the surface of New Earth. Because it smells like apples.
* FantasticRacism: Cassandra (once again) dismisses humanity's other descendants as mutants unworthy of the name human. Rose retorts that they just evolved, while Cassandra has mutilated herself rather than move with the times.
* FateWorseThanDeath: Rose [[TemptingFate claimed to be horrified]] at the idea of living on like Cassandra and now actually ends up being possessed, with Cassandra [[BestServedCold doing this on purpose to force such a fate upon Rose]] and turning her into the thing she claimed to hate the most in Cassandra; [[TheSocialDarwinist an elitist]] and [[EvilBrit supremacist villainess]].
* FemmeFatale: A Cassandra-occupied Rose takes on this role during the episode, portraying on-screen how she might've [[TheTease "inherited"]] the fortunes of her several husbands in the past (as mentioned in [[Recap/DoctorWhoS27E2TheEndOfTheWorld "The End of the World"]] and expanded upon in [[AllThereInTheManual supplemental material]] by Creator/RussellTDavies). It's an interesting contrast [[EvilCounterpart when compared]] to Rose's role as the Doctor's companion, since "Rose" hides her true intentions and tries to seduce the Doctor when she joins him on his investigation of the Sisters, going so far as to make out with him while only arousing ''some'' suspicion about her [[NotHerself change of personality]]. Her detective work is what helps the Doctor find out the secrets of the hospital, before she turns on him like in classic, FilmNoir fashion. [[MeaningfulName Cassandra surely gives her own name justice]].
* FetishizedAbuser: Rose is forced into the role when she gets possessed by Cassandra, aggressively taking the initiative in helping the Doctor uncover the hospital's Intensive Care and [[ShamelessFanserviceGirl showing off her sex-appeal]]. Since Cassandra is a high-class lady and Rose is a young woman of a humble background, they fit the "sexy lady" and "sexy girl" versions simultaneously, due to [[FusionDance being merged together]]. Strangely, the Doctor doesn't seem to mind Rose's change of personality that much and just keeps up with her seductive approaches on him until her [[LackOfEmpathy apathy]] blows her cover.
* FlyingCar: Seen in establishing shots for the "this is the future" feel.
* FoeRomanceSubtext:
** Cassandra has a lot of this with the Doctor, due to Rose's influence after possessing her. Despite the fact that she does admit her lust towards him, at the end of the episode when she [[JerkWithAHeartOfGold goes back to her old self]], she seems to be ok with Rose and the Doctor being together and likes [[ShipperOnDeck to tease them about it]].
** Cassandra has some of this with Rose too. Basically, Cassandra loves and hates being [[FusionDance merged with Rose]] at the same time. (Because she admires her beauty and yet can't get over her own classist hatred.)
* {{Foil}}: Besides the two representing [[LightFeminineAndDarkFeminine opposite ideals of femininity, Cassandra and Rose]] are further contrasted to explore the themes of conflicting class backgrounds, youth and age, past and future values, and what it means to be human. As in [[Recap/DoctorWhoS27E2TheEndOfTheWorld "The End of the World"]], they are both presented as being the last "pure" humans (this may be a reference to the [[RichBitch stereotypes]] that they [[WorkingClassHero represent]] in British society and being "human" is a meaningful aspect of their characters). But while the upper-class Cassandra seems fixated on keeping the material aspects of what she considers make her human, looking down on the hybrids, Rose sees humans evolving as something natural. She's learned from her experiences since Platform One and hasn't [[CynicismCatalyst become cynical]] like Cassandra. This gets further attention once Cassandra takes over Rose's body: she removes nearly all the qualities that make Rose "human".
** [[FusionDance Cassandra/Rose]] is this to normal Cassandra. While her personality remains mostly the same, she is still somewhat different, not being nearly as hammy and instead acting [[IceQueen like the Ice Queen.]] She also seems to have gained Rose's love for adventure and is also infatuated with the Doctor, flirting with him and actually enjoying her role as her companion, not bothering to reveal her facade until much later.
* {{Foreshadowing}}:
** Cassandra calls attention to the film projection of her past human self at an extravagant drinks party as "the last time anyone told me I was beautiful". A couple of scenes later, as a Cassandra-possessed Rose tests out her new body in front of the reflector, Chip praises his mistress as [[MeaningfulEcho "beautiful!"]], seeding his (and Cassandra's) role at the end of the episode.
** As the Doctor prepares to distribute his concoction of cures via the disinfectant lifts to save the day, he tells Rose/Cassandra to pull a lever and [[Recap/DoctorWhoS28E13Doomsday "hold on to it with everything you've got"]].
* FunnyBackgroundEvent: During Rose/Cassandra's "bouncy castle" scene, as she jiggles up and down in front of the mirror, Chip can be seen in the background ''bouncing along with her'' like a small child. Moments later, she ogles her rear end, and Chip takes a good look, too.
** Rose/Cassandra in the background of Creator/DavidTennant's big shouting scene as the Doctor in the Intensive Care unit, and again during his quiet chat with The Face of Boe. Both times, she's seen [[PrimpOfContempt striking bored poses]], rolling her eyes and taking no interest whatsoever in the conversation.
* FusionDance: A dark take on it. While Cassandra becomes the dominant personality in the possession, she is still influenced by Rose emotionally, claiming it’s hormone season inside her head, and seems to have gained Rose's feelings towards the Doctor too. Cassandra also does this forcefully with Rose.
* GenderBender: This is happening when Cassandra is possessing the Doctor's body. The result is basically if David Tennant were playing Characters/AustinPowers.
* GoodHairEvilHair: Rose's haircut at the start of the episode is supposed to represent her growing confidence as a person. This takes a dark turn once Cassandra possesses her body, since [[https://tragicalhistorytour.com/d11/8p-c/d11-8p-c204.jpg she disarrays Rose's hair]] to resemble [[https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fstatic.tvtropes.org%2Fpmwiki%2Fpub%2Fimages%2Fdrwho_wanamaker_600x300.jpg&f=1&nofb=1 Zoe Wanamaker's style in her Cassandra scenes,]] with it partially obscuring her face. Unironically, part of the reason why Cassandra chooses Rose as her host is because [[EveryoneLovesBlondes she likes the idea of becoming a blond again]].
* AGodAmI: Averted, believe it or not, by Cassandra. Despite having someone who explicitly "worships her", she doesn't think of herself as a god.
* GoSeduceMyArchNemesis: [[PlayedForLaughs Played For Laughs.]] This is a big part of Cassandra's plan. Since she sexualizes Rose's appearance to such an extent, It's implied she was [[DirtyOldWoman even willing to do the dirty deed with the two of them if necessary.]]
* GracefulLadiesLikePurple: The way Cassandra wears Rose's patterned purple blouse after possessing her, reflecting her darker, haughtier and sultrier personality as a noblewoman.
* GrandTheftMe: Cassandra does this with a lot of people: Rose, the Doctor, one of the clones and Chip, but Chip doesn't count. He explicitly volunteered for it.
* GratuitousFrench:
** Cassandra, pleased with her bouncy new body:
--->'''Chip:''' The mistress is beautiful!\\
'''Rose/Cassandra:''' ''Absolument!''
* GreatDetective: Rose does this but with a dark twist. Cassandra's possession boosts her detective skills, allowing her to figure out the secrets of the hospital in no time at all and Cassandra also makes an effort to exploit her looks as she investigates with the Doctor, becoming a [[FemmeFatale Femme Fatale version of this trope.]]
* HairFlip: Cassandra does a dramatic one of these while she's getting ready to rejoin the Doctor as [[FanservicePack a more sexed-up version of Rose]]. It steals a lot of the thunder from Chip's [[TheBeCarefulSpeech "Beware The Doctor" pep-talk]].
-->'''Chip:''' This Doctor man is dangerous-\\
'''Rose/Cassandra:''' ''[tosses her hair back breathlessly]'' Dangerous and ''clever''. I might need a mind like his.
* HappinessInSlavery: Chip lives to serve his mistress Cassandra, who doesn't even consider him a proper life-form and refers to him as her "pet" even though he has independent thought of his own. When the Doctor protests at Cassandra possessing Chip in the episode's dénouement, Chip seems highly offended, and willingly volunteers his body as her next (and final) vessel.
* TheHedonist: Cassandra is once again portrayed as such. She sexualizes both Rose's and the Doctor's bodies, makes out with the Doctor and actually seems to enjoy her role as the Doctor's companion, [[ThrillSeeker smirking in excitement]] after they discover the entrance to Intensive Care. She doesn't even bother revealing her facade until the Doctor starts getting paranoid about her behaviour. A deleted bit in the Ward 26 scene had her accepting some champagne off the Duke of Manhattan.
* HighVoltageDeath: One of the diseased test subjects deliberately sacrifices himself to short-circuit the Intensive Care systems and create a power surge which releases the others from their pods.
* {{Hypocrite}}:
** After discovering the identity of Rose's gentleman friend, Cassandra mistakes the Doctor for one, assuming his [[TheNthDoctor new look]] to be the result of plastic surgery.
--->''"...the same Doctor, with a new FACE! That HYPOCRITE! I must find the name of his surgeon."''
** Despite Cassandra verbally abusing Rose about how vulgar and classless she is according to her, out of the two Cassandra is much more [[AttentionWhore unrestrained]] and [[ShamelessFanserviceGirl lustful]] when compared to Rose, despite being more stylish.
** While claiming to be willing to get rid of her and displaying significant amounts of classist hatred, Cassandra makes a point in protecting Rose as long as she remains as her host and is rather [[ProudBeauty pleased with her new appeal after possessing her]]. If given the opportunity to regain her wealth, Cassandra may have even gotten over her classist hatred and fully [[VillainRespect embraced Rose as an equal]] that she can continue to possess in order to live on as a [[TheSocialDarwinist supremacist villainess]] allowing her to [[FateWorseThanDeath get her revenge on Rose as well]].
* IceQueen: Cassandra behaves in this fashion while possessing Rose. In contrast to her usual self who was more likely to [[EvilIsHammy express herself]], she is more aloof, refined and ironically more lady-like as Rose. Maybe as way for Cassandra to cope with [[LowerClassLout the resentment towards her host]]. This apathy of hers causes the Doctor to [[TrojanHorse figure out Cassandra's ruse]].
* IconicOutfit: Rose's "inside-out" blue and purple button-down shirt that she wears for most of the story. Donna Noble later finds it in the TARDIS in [[Recap/DoctorWho2006CSTheRunawayBride "The Runaway Bride"]].
* IgnoreTheFanservice: When a Cassandra-possessed Rose rejoins the Doctor in Ward 26, he's too busy showing her all the miracle patients and cured diseases to notice she's walking rather differently and wearing her shirt a lot lower than she usually would, so it's a bit of a shock when she [[TheBigDamnKiss makes out with him]].
* ImprovisedWeapon:
** Suspicious of Chip's intentions as he lures her to the basement, Rose picks up a metal rod to defend herself.
** When the Doctor and Rose/Cassandra make it back to Ward 26, Frau Clovis initially believes they've been infected and charges at them wielding a visitor's stool.
* IneffectualSympatheticVillain: Cassandra gets this treatment in contrast to her [[ClassicVillain more serious debut]] in "The End of the World". She is [[BestServedCold still a villainess out for revenge]], but her villainous traits [[PlayedForLaughs are mocked]] and even [[ComicRelief added]] for its comedic value, her plans fail her and get her in trouble and [[ShamelessFanserviceGirl she even gets to be the source for most of the fanservice]] during the story... [[GrandTheftMe unfortunately]] for [[ReluctantFanserviceGirl Rose, of course]].
* InstantIllness: The slightest touch from the diseased test subjects is fatal: anyone infected by them immediately breaks out into boils and dies horribly. In the Doctor's own words, the clones are carriers of "every single disease in the galaxy".
* InstantSoprano: When Cassandra - in Rose's body - kisses the Doctor completely out of the blue, the latter freezes for a couple of seconds during Post-Kiss Catatonia, before muttering how he's "still got it" in a very squeaky voice.
* TheIntern: Novice Hame.
* {{Irony}}:
** Despite being apathetic about it at first, Cassandra's help in curing the Flesh ends up creating a whole new race of humans, which she eventually grows fond of.
** Back in [[Recap/DoctorWhoS27E2TheEndOfTheWorld "The End of the World"]], when Rose is offended by Cassandra's arrogance, she claims that Cassandra isn't the last human being in the room -- that it's actually Rose herself. While this can be interpreted as a [[FantasticRacism racial attack against Cassandra herself]], it can also be taken as Rose pointing out that despite her materialist views, Cassandra doesn't even resemble a human being anymore. When they meet again here, Rose ends up becoming [[EvilBrit Lady Cassandra in the flesh]], when she's possessed, precisely because she fits [[TheSocialDarwinist Cassandra's racial eugenics]] and conservative ideals. It's also the perfect chance for Cassandra to [[BestServedCold make Rose pay]] for her racist claims against her.
** When Rose finds out that Cassandra's new skin is now taken "from her back", she sarcastically comments that she is talking out of her own... "Ask not!" Cassandra interrupts. After trapping Rose in the psychograft and possessing her, Cassandra wonders [[EvilMakeover what plastic surgery she can do this time around on Rose's body in order to improve her new appeal ]] but [[ProudBeauty takes great pleasure in admiring her posterior]], quite possibly [[BestServedCold on purpose as a means of getting back at Rose]]. Basically, [[{{Satire}} Cassandra is "talking out of her own (Rose's) arse"]]...
** Despite all her arrogance when it comes to considering herself "The Last Human", Cassandra finally comes to the realization that she was the least "humane" character in the end, finally regaining the good in herself.
* IWasQuiteALooker: Once upon a time, skin trampoline Cassandra looked like Creator/ZoeWanamaker, complete with blonde curls and a glamorous silver dress. After that, as she laments to Rose, "it all became... such hard work".
* KarmicDeath: Both cat nuns who callously execute a clone man begging for help are later killed by the diseases carried by the clone people.
* LackOfEmpathy: In the end, it isn't Cassandra's dodgy Cockney accent, enthusiastic kissing, familiarity with five-billion era tech or her FemmeFatale portrayal of Rose which eventually give her away to the Doctor, but her complete apathy and lack of revulsion for the plight of the diseased Intensive Care test-subjects.
-->'''The Doctor:''' These people are dying, and Rose would ''care''.
** Later subverted in the episode when Cassandra briefly inhabits one of the plague-carriers and is visibly shaken at having felt their pain and loneliness for herself, undergoing a HeelRealization. Her final scene, as the Cassandra of the past cradles Chip's (her future self's) body in her arms and calls for help, is further evidence that she was once a more empathetic person.
* LargeHam: Cassandra bleeds over into Creator/BilliePiper ("It's like living in a bouncy castle!!") and Creator/DavidTennant ("a little bit fox-ay!") when the Doctor and Rose end up hosting Cassandra's personality.
* LastOfHisKind:
** The Face of Boe doesn't get many visitors because the rest of Boekind died out a long time ago. No wonder his message is meant for the Doctor.
** Cassandra once again refers to herself as [[Recap/DoctorWhoS27E2TheEndOfTheWorld "The Last Human"]] and refuses to recognize the people of New Earth as such, despite Rose rightly pointing out that humanity has continued to survive by embracing the need to evolve and change. Even after possessing Rose, she still calls herself by this title when confronting the Doctor as a reflection of her [[VillainRespect respect towards Rose as a worthy vessel]].
* LightFeminineAndDarkFeminine: Cassandra and Rose represent radically opposite ideals of femininity.
* LimbSensationFascination: Having not had a body to call her own for centuries, the first three things Cassandra notices upon possessing Rose, are, in order: "Arms...fingers...hair!"
* LiteralMinded: Rose/Cassandra is in the middle of [[ManIFeelLikeAWoman feeling up her new derriere in front of the mirror]] when she receives a phone call from the Doctor and briefly wonders if Rose's bum is meant to ring:
-->'''Rose/Cassandra:''' I must get the name of his surgeon. I could do with a little work. Although...''[she caresses Rose's bottom]'' Nice rear bumper...Hmmm...\\
''[Rose's mobile rings in her back pocket]''\\
'''Rose/Cassandra:''' Oh! It seems to be ringing! Is it ''meant'' to ring?\\
'''Chip:''' A primitive communications device.
* LiteralSurveillanceBug: Cassandra is using one of her spider-like robots from [[Recap/DoctorWhoS27E2TheEndOfTheWorld Platform One]] to spy on the planet's surface.
* LockedInAFreezer: The Doctor is knocked unconscious by Cassandra and locked in one of the [[PeopleJars stasis pods]] in Intensive Care which are automatically pumped full of disease every ten minutes. When he wakes up, Cassandra tells him he has about three minutes to live.
* LoopholeAbuse: In a longer version of the scene where Cassandra/Rose blackmails the Sisters that was ultimately shortened in the final episode, she identified herself by her full title and taunted the nuns with their vow that they're forbidden to harm any living thing. While they talked, Sister Jatt would access human medical records and discover that the Lady Cassandra died many years ago (which is why she is suddenly seen tapping away at a Palm-Pilot DataPad as shown in the top page image), thus giving the cat nurses the technicality they need to kill her.
* LowerClassLout: Cassandra invokes the "snob calling someone a chav" version towards Rose while engaging in GrandTheftMe.
* {{Lust}}: In addition to her obsessions with status and beauty, finally having a proper body again reawakens Cassandra's sexuality. She comes to [[DistractedByMyOwnSexy appreciate Rose's figure]] and uses it in an attempt to seduce the Doctor, leading to her hot-and-heavy snogging of him in Ward 26. Cassandra later suggests that this same desire comes from Rose's mind as well. Bearing in mind that this is the same man who "killed" her in their last encounter...
* LustObject: Despite her [[LowerClassLout classist views towards Rose]], Cassandra all but idealizes her host in this way, admiring and appropriating Rose's body for her own ends until she's positively [[DistractedByMyOwnSexy drunk on her new sex-appeal]]. The Doctor briefly becomes this to her as well, right up until he blows her cover.
* MagicPlasticSurgery: Cassandra seems to think the Doctor's new face is due to this; hence why she calls him a hypocrite for scorning her own surgery.
* MakeupWeapon: Cassandra's perfume, [[VictoriasSecretCompartment which she tucks down Rose's décolletage for safekeeping]], is actually a noxious [[KnockOutGas sleeping spray]] that certainly comes in handy once the Doctor exposes her charade.
* MaleGaze: Mostly averted during the Cassandra-in-Rose scenes, since the camera tends to keep Creator/BilliePiper in full frame even while she [[ShowingOffTheNewBody checks herself out in front of the mirror]] and provides plenty of {{Fanservice}} throughout the episode. There ''is'' a lingering medium close-up showing her [[VictoriasSecretCompartment stuffing perfume down her top]], ''twice'', but one could argue that's plot-motivated...
* ManIFeelLikeAWoman: Cassandra spends the episode jumping around being Creator/BilliePiper, Creator/DavidTennant and a couple of other people. "Goodness me, I'm a ''man''!"
* MeaningfulAppearance: Cassandra's [[EvilCostumeSwitch clothes and makeup after possessing Rose]] represent the [[LowerClassLout vulgar and brassy way]] in which she sees her, but also how proud she has become of [[BigBreastPride her new assets]] and [[ProudBeauty figure in general]].
* MessianicArchetype: The Doctor calls all the disease-ridden clone-people to him so he can cure them with a sprinkler (baptism) and then sends them out to cure others by [[HealingHands laying on hands]] like the apostles.
* MultipleReferencePun: From Matron Casp:
-->'''The Doctor:''' How on Earth did you cure him?\\
'''Casp:''' How on ''New'' Earth, you might say!
* MurderByCremation: The Sisterhood's standard procedure whenever the Intensive Care test subjects show any signs of sentient life is to [[KillItWithFire incinerate them in their pods]].
* {{Narcissist}}: Cassandra is a dangerous megalomaniac and xenophobe convinced of her own superiority. In classic fashion, [[VillainousCrush she even falls in love with her own reflection after possessing Rose]].
* NoEscapeButDown: Cassandra refuses to accompany the Doctor on his daredevil plunge down a lift shaft... until Frau Clovis locks her out of Ward 26 with an approaching group of the infected, leaving her no choice but to jump on his back.
* NoNewFashionsInTheFuture: The nuns aside, clothing styles don't seem to have changed much in the year five billion. Most of the hospital visitors appear to be wearing regular modern-day fashions, and there is apparently still the need for corrective eyewear, in the case of the Duke of Manhattan's assistant Frau Clovis.
* NoOntologicalInertia: Played straight. The Doctor uses a vaccine to cure the patients, complete with the visible signs of their illness disappearing before our eyes.
-->''"I'm the Doctor, and I ''cured them!''"''
* NotHerself: Rose, after being possessed by Cassandra. The Doctor can tell because Rose would care about the people locked up for cures, and Cassandra does not.
* NotRightInTheBed: The Doctor notices Rose's sultry change in personality right away but it gets averted once she actually kisses him, with him thinking it's a result of his new charm when [[EnemyWithin she is actually possessed]].
* OhCrapSmile: Rose/Cassandra's nervous grin when her attempt to blackmail the Sisters fails and they menace her with their claws:
-->''"Well, nice try!"''
* OlderThanTheyLook: [[FusionDance Cassandra/Rose]] is physically around 20 but billions of years old mentally.
* TheOneThingIDontHateAboutYou: Despite her vindictiveness towards both, Cassandra admires both Rose and the Doctor for their looks and reduces their bodies to [[LustObject mere objects for her pleasure]] after possessing them, reflecting her [[BeautyIsBest superficial outlook]].
* OohMeAccentsSlipping: Cassandra-possessed Rose sports Billie Piper's normal Received Pronunciation accent, then puts on a REALLY bad Cockney accent for the Doctor's benefit. And that's not even getting into the Cassandra-possessed Doctor, which is basically David Tennant trying to channel Austin Powers whilst doing a cross between Cassandra's RP and the Doctor's Estuary English accent.
* OpinionFlipflop: Used lightly by the Doctor. When attempting to reason Cassandra out of Rose's body (and thus to her inevitable death), he insists that there is no other way, and her time is over. When she instead uses Chip as a host (something the Doctor cannot forbid because he is a volunteer) he quickly relents and offers to keep her alive in a skin tank if she leaves his body.
* OurClonesAreDifferent: Cassandra O'Brien was able to "force-grow" a clone called Chip, whose appearance she modeled on a man she'd met long ago: Cassandra implicitly imprinted Chip's likeness on him from her own memory without any DNA samples from the "original" actually being used. Chip has a "half life", which causes him (physically appearing to be a young man) to die of organ failure at the episode's end. The clone patients were artificially grown the sisters of plentitude to use as test subjects but it's unknown where they got DNA samples from.
* OurZombiesAreDifferent: The clone-people are {{Technically Living Zombie}}s who are able to transmit the diseases they carry to anyone with one touch. They're driven by a [[DesperatelyCravesAffection need for touch]] (and implicitly also {{revenge}} on their abusive creators) to touch anyone else they come across without any regard for the consequences.
* OutgrownSuchSillySuperstitions: Averted. The Sisters of Plentitude are a Religious order that exists over five billion years in the future and worships a goddess named Santori.
* OutOfCharacterAlert: The Doctor accepts Cassandra-possessed Rose's explanation of her atrocious Cockney accent as "just larking about," and chalks up her kissing him out of nowhere to him retaining his charm post-regeneration, but he knows something's been done to her once she starts displaying unusual computer smarts and reacts to the diseased clone-people with disgust rather than compassion.
* ParadisePlanet: What little we see of New Earth outside the hospital consists of rolling green hills and gleaming super-advanced cities.
* PeopleFarms: The clone-people are grown in test tubes by the Sisterhood to assist in their cure research.
* PeopleJars: The clones are kept in these.
* PercussiveMaintenance: Cassandra/Rose rips some wires out of the wall to sound the alarm after she knocks the Doctor unconscious.
* PerpWalk: Novice Hame is arrested by the police and led away in shame past the Doctor and a Cassandra-possessed Rose at the end of the episode.
* PersonalityPowers: Being the FemmeFatale that she is, [[MeaningfulName Cassandra]] likes to project an image of trust before going after her prey, so she gains the ability to possess people, [[TrojanHorse allowing her to pretend to be whoever she wants to be]]. Being the [[ClassicVillain villainous archetype that she is]], It's also [[AntagonistAbilities a power related to such figures]].
* PetTheDog:
** Despite her usual racist views, we are shown through Chip that Cassandra values the people that remain loyal to her, and she never forgot about his face since he was the last person to admire her beauty.
** Despite possessing her out of her desire for revenge, Cassandra grudgingly praises Rose's good looks and [[TheSocialDarwinist accepts her as a decent pure-blood]] who she can inhabit until she finds a better host.
** Cassandra later accepts the Flesh as a new form of life, and through them, she realizes where [[HiddenHeartOfGold her true value really lies]], going back to [[JerkWithAHeartOfGold her old self]].
** Despite still holding a grudge against her actions, (and the Doctor actually makes it clear in a deleted scene) the Doctor is willing to offer Cassandra an alternative in order to continue living that she declines because she accepts her time has come. Later on, he grants her a final chance to come to terms with her past.
** While Rose is obviously disturbed about Cassandra seeking to [[EnemyWithin kill her from within]] and turning her [[GrandTheftMe into her new host]], being [[ReluctantFanserviceGirl forced to provide most of the fanservice throughout the episode]], in the usual fashion, Rose is willing to forgive Cassandra for her actions and goes with her and the Doctor so she can say her final words to her young self. Once again showing what makes Rose human.
** To a vain extent, Cassandra (while possessing Chip) even gives one to herself when the Doctor allows her to enjoy her favourite moment, the night someone told her she was beautiful. She tells her younger self she's beautiful the way she is, to which past Cassandra is moved enough to [[SincerityMode gratefully]] say "Thank you."
* PlanBResolution: When Cassandra's attempt to blackmail the Sisterhood fails, she has to quickly come up with a Plan B. This involves having Chip release a row of the infected clones from their {{People Jars}} in order to cover her escape.
* PoliticallyIncorrectVillain: Cassandra as usual because of her conservative ideals. This time around however, Rose gets [[PlayedForLaughs hilariously]] forced into the role as well due to Cassandra possessing her. [[FusionDance Rose/Cassandra]] is extremely vain and haughty about her [[TheSocialDarwinist racial purity]] and [[ProudBeauty good looks]], resents [[LowerClassLout her lack of wealth]] and sees herself as [[LastOfHerKind "The Last Human"]], looking down on [[AbsoluteXenophobe everybody else as mongrels]].
* PossessionBurnout: The Doctor mentions Cassandra's psychograft is an illegal device "banned on every civilized planet" and that she's "compressing Rose to death", suggesting the process is unstable.
** This is reflected in Rose's discombobulated state and increasing fatigue every time Cassandra stops possessing her. When she leaves her body for good at the end of the episode, Rose is so worn out she [[FallingIntoHisArms literally collapses in the Doctor's arms]], but recovers shortly thereafter.
** Chip isn't so lucky. Due to the ordeal of the day's events and his shortened clone lifespan, his heart is already under a lot of strain when Cassandra takes over his body, and he ends up becoming his mistress's final host.
* PostKissCatatonia: The Doctor after Cassandra-in-Rose's-body snogs him.
-->'''The Doctor:''' ''[squeaky]'' Yep. Still got it.
* PoweredByAForsakenChild: The Sisterhood's fast-acting medicine is powered by a veritable plethora of clones infected with ''everything''.
* PrimAndProperBun: The Duke of Manhattan's uptight, severe-looking assistant, Frau Clovis.
* PrincessInRags: Despite being pleased with her new looks, Cassandra is still rather angsty about the idea of being a [[LowerClassLout vulgar chav and having lost her wealth]]. She is determined about [[TheUnfettered getting her social status back regardless]].
* ProperLady: Cassandra averts this at first, since she embodies many [[ClassicVillain "Evil Lord/Lady" tropes]]. But at the end when she helps saving the Flesh, she realizes how wrong she was about her Darwinist ideals and starts acting in a [[TookALevelInKindness much more caring way towards]] the Doctor, Rose and the Flesh, [[ShipperOnDeck even supporting the Rose and the Doctor being together]]. Despite this being [[JerkWithAHeartOfGold her original personality]], she unfortunately doesn't atone for her sins or goes full heroine (or [[AntiHero anti-heroine in her case]]), because she perishes shortly after. At least she seems to be happy with the Flesh prospering as a new form of life.
* ProudBeauty: Played mostly straight by Cassandra (in spite of her initial shock) when it comes to judging her new (Rose's) appearance; to the point that [[ShamelessFanserviceGirl she goes out of her way to make sure everyone notices her new appeal]]. For a high-class lady, Cassandra seems to [[DirtyOldWoman enjoy her new image more than usual]]. But then again, she did just gain [[MsFanservice Billie Piper's looks]]...
* PsychicBlockDefence: Cassandra mentions the Doctor's "hidden away all his thoughts" after she possesses him, preventing her from using his sonic screwdriver.
* PunctuatedForEmphasis:
-->'''Rose:''' ''[laughing]'' Right, so you're talking out your--\\
'''Cassandra:''' ''Ask. Not.''
* RattlingOffLegal: [[ObstructiveBureaucrat Frau Clovis]] is quick to remind the Doctor of the ludicrously protective rules and decrees surrounding her boss, the Duke of Manhattan:
** Members of the public may only gaze upon the Duke of Manhattan with written permission from the Senate of New New York.
** Any statement by the Duke of Manhattan may not be made public without official clearance.
** Any friendship from the Duke of Manhattan does not constitute a form of legal contract.
* RecycledSoundtrack: With the exception of the Face of Boe's plaintive melody, a lot of the episode's score is re-used from Series 1, perhaps as a way of bridging the gap and reminding viewers this is still the same old show. "Cassandra's Waltz" from [[Recap/DoctorWhoS27E2TheEndOfTheWorld "The End of the World"]] makes a return, as does the "Westminster Bridge" music from [[Recap/DoctorWhoS27E1Rose "Rose"]], both in the story's pre-credits sequence and during the climax.
* ReluctantFanserviceGirl: Halfway through the story, Rose gets a sexy new look and shows a lot more skin than she usually does. But since [[GrandTheftMe her body is possessed by Cassandra]] at the time, it isn't by choice.
* ReversePsychology: A masterful example from Cassandra. She tells Rose that the cat nurses have been keeping a secret, and asks her to come in close so she can whisper it in her ear. Rose laughs at such an obvious trap, and instead takes a step back and ends up immobilised by the [[GrandTheftMe Psychograft]].
* RichesToRags: After [[Recap/DoctorWhoS27E2TheEndOfTheWorld her defeat on Platform One]], Cassandra's clearly had to downsize a lot and it's implied she lost most of her fortune. Having crudely reconstructed herself using skin from her back(side), she's reduced to hiding alone in the hospital basement, relying on a single servant, Chip, to steal the medicine she needs to survive. Her army of metal spiders appears to have dwindled down to just one, and instead of the sophisticated pump-spray guns previously carried by her surgeons, Chip moisturises her with a rudimentary squirt bottle. When she ''does'' find a new pure-blooded human body to inhabit, it's that of her [[WorkingClassHero brassy arch-nemesis]], Rose Tyler.
* RichLanguagePoorLanguage: It's used in order to point out the class warfare subtext between [[ArchEnemy Cassandra and Rose]]. Instead of her usual London accent, Billie Piper uses her natural Posh dialect when Rose gets possessed by Cassandra, although a bit more exaggerated to sound more mature. Some people even thought that Zoe Wanamaker was still doing Cassandra's voice during the possession. Indeed, it almost seems like a [[EvilBrit posh, cynical old lady is at the scene who just so happens to resemble Rose]].
* RoomFullOfZombies: The plague-carriers spill out into the rest of the hospital when one of the nuns escorting some visitors through the ward opens a door and finds it packed floor-to-ceiling with diseased test-subjects, who proceed to infect them.
* RuleOfThree:
** The Sisters of Plenitude are represented by three main, unveiled cat nuns with three different ranks: Matron Casp, Sister Jatt and Novice Hame.
** The hospital lifts have three stages of disinfection.
** The hospital's official motto values three things: "Hope, harmony and health".
** The Doctor and Rose visit Ward 26 at three different points during the episode. All three times, Rose is still possessed by Cassandra.
** Frau Clovis lists three separate disclaimers regarding the Duke of Manhattan, and Cassandra's refrain of "Moisturise me!" is repeated three times in the episode.
** Rose is possessed by Cassandra on three occasions, checks herself out in the mirror three times, answers her phone on the third ring, and wears her blouse throughout the story with three out of the five buttons done up.
** The "Old Earth saying" Cassandra quotes to Chip contains three warnings: "Never trust a nun, never trust a nurse and never trust a cat."
** The Doctor name-checks three different diseases in the hospital: Petrifold Regression, Marconi's Disease and Pallidome Pancrosis. Later, three different characters (two cat nuns and a visitor) are seen to be infected onscreen by the Intensive Care subjects.
** The Face of Boe promises the Doctor a third and final meeting.
* RunningGag: The Doctor's fondness for [[Recap/DoctorWhoS29E1SmithAndJones little]] [[Recap/DoctorWhoS30E8SilenceInTheLibrary shops]] begins here. He's disappointed the hospital doesn't have one.
-->'''The Doctor:''' Nice place. No shop downstairs, though. I'd have a shop. Not a big one, just a... shop. So people can... shop.\\
'''Sister Jatt:''' The hospital is a place of ''healing''.\\
'''The Doctor:''' Well, a shop does some people the world of good. Not ''me''...other people.
** This episode also marks the beginning of Ten kissing absolutely everybody.
* StalkerWithACrush: Cassandra spends the episode possessing different people but targets Rose the most in particular because she [[FantasticRacism is the only other pure-blooded human by Cassandra's standards]]. She also has strong, [[{{Yandere}} contradictory feelings towards her host]].
* SaintlyChurch: The Sisterhood run a hospital founded by charity to heal the sick. They take ''oaths'' to do nothing but heal the sick. One of them says that the "people farm" thing was a last resort because nothing else they tried worked fast enough to heal all the sick people coming to them. When Cassandra releases the clone-humans, they quarantine the hospital to prevent anyone else from getting sick. They are still in the hospital when this happens.
* SecretRoom: The hospital's massive, multi-level Intensive Care department, where the Sisters grow vast {{People Farms}} as guinea pigs for their medical cures.
* SensibleHeroesSkimpyVillains: Compare Rose's modest zip-up jacket with the sexy patchwork blouse she wears later on, [[ShowingOffTheNewBody buttoned down to reveal her cleavage]], when Cassandra possesses her.
* SequelEpisode: To [[Recap/DoctorWhoS27E2TheEndOfTheWorld "The End of the World"]].
* SignificantWardrobeShift: Starting with this episode, Rose starts wearing brighter and bolder colours along with more sophisticated outfits. This, along with her hairstyle change, is supposed to symbolize her growing confidence as a companion and a person. This ironically takes [[DarkerAndEdgier a darker turn]] once [[EvilCostumeSwitch she gets possessed by Cassandra]].
* ShamelessFanserviceGirl: Cassandra ends up becoming this after possessing Rose. Yeah, the [[BodyHorror monstrous and alien-like]] serious [[EvilBrit conservative villainess of the plot]] ends up [[PlayedForLaughs becoming]] one of the [[MsFanservice sultriest characters]] in the series. Is it a case of [[CameBackStrong Came Back Strong]] or rather, [[FanservicePack Came Back Foxier than ever?]]
* SharePhrase: All the diseased humans from Intensive Care whisper variations of "Please...", "Help us..." or "Save us..." as they overrun the hospital.
* ShipTease: This being David Tennant's first full outing as the newly regenerated Doctor, this Season 2 premiere sets up a fresh new relationship dynamic between the Doctor and Rose. From the outset, the two are presented as being clearly attracted to each other, enjoying a closeness and comfort with each other's company that's more than just platonic and obviously related to the Doctor's [[TheNthDoctor recent change in appearance]]. The episode's opening minutes are even akin to a romantic picnic, with the Doctor and Rose relaxing together on his coat, holding hands and [[HeldGaze staring into each other's eyes]]. Rose gushes about how she ''loves'' travelling with him and refers to their previous visit to the year five billion as "[their] first date", something the Doctor doesn't contradict. This more tactile rapport is [[ShipperOnDeck complicated by Cassandra]], who recognizes the sex appeal of both their bodies when she possesses them and plays up the physical, flirtatious side for her own ends. In Rose's case, she refashions her into a coquettish, more exaggeratedly feminine FemmeFatale version of herself, and her [[TheBigDamnKiss Big Damn Kiss]] with the Doctor seems just as much a case of her acting on Rose’s feelings for him than satisfying her own carnal urges (the Doctor meanwhile, is rather shocked by his companion’s sudden outburst of affection and attributes it to his own natural charisma). In the Doctor's case, she teases Rose with the knowledge of [[EatingTheEyeCandy her attraction to the Doctor]] and it being "hormone city" inside her head.
* ShoutOut:
** The Doctor says that the city they landed near is called [[WesternAnimation/{{Futurama}} "New New York"]].
** Chip and Cassandra are seen watching the Doctor and Rose through a reddish-tinged orb conveying the POV of one of her metal spiders, not unlike the way the Wicked Witch of the West uses a crystal ball to spy on Dorothy in 1939's ''Film/TheWizardOfOz''.
** Admiring the hospital's smart, minimalist decor, Rose comments it's quite different from the UsefulNotes/NationalHealthService she has back home.
** Rose disparagingly refers to Chip as [[Film/TheLordOfTheRings "Gollum"]].
** The term "bouncy castle" was previously used as a physical description in the Creator/RussellTDavies production ''Series/QueerAsFolkUK''.
* ShowingOffTheNewBody:
** Cassandra does it as soon as she takes over Rose:
--->'''Rose/Cassandra:''' Look at me! From class to brass! Although... ''[unzips her shirt and runs her hands over her body]'' Ooh... curves... oh, baby... ''[bounces up and down]'' It's like living inside a bouncy castle!
** And the same for the Doctor:
--->'''Doctor/Cassandra:''' Ooh, my! This is... different.\\
'''Rose:''' Cassandra?\\
'''Doctor/Cassandra:''' Goodness me, I'm a ''man!'' Yum! So many parts ... and hardly used! ''[he begins shaking as she discovers the Doctor's binary vascular system]'' Ah! Ah, two hearts! Oh baby, I'm beating out a samba!
* ShrineToSelf: Cassandra spends most of her time in her dungeon lair watching a projected film of her former self at a drinks party "for the Ambassador of Thrace" and reliving memories of her glamorous past. Specifically, the last time anyone called her beautiful.
* SicklyGreenGlow: The tanks the clones are kept in are lit like this.
* SnarkToSnarkCombat: Rose and Cassandra engage in this when the two meet in her dungeon lair.
* TheSocialDarwinist: As in her previous appearance, Cassandra retains her conservative ideals, which is also why she chooses Rose as a host. Not only does she hate people that don't fit her idea of "purity", but she also hates lower-class people because of their "weakness". A lot of her angst after possessing Rose isn't because she doesn't like her new image, [[ProudBeauty quite the opposite]], but rather, it's because she can't stand the idea of being a [[LowerClassLout "weakling" herself]]. Cassandra still proudly calls herself [[LastOfHerKind "The Last Human"]] even while possessing Rose, because [[FantasticRacism she believes Rose fits her racial eugenics and ideals of beauty]].
* SomethingOnlyTheyWouldSay: After seeing "Rose" act callous towards the Flesh, the Doctor was alerted that ''something'' was inhabiting his friend, but it's only this line that lets him know ''who'' it was:
-->'''The Doctor:''' Who are you?\\
'''Cassandra:''' ''[leans in towards his ear]'' ...The last human...
* SpareBodyParts: Cassandra is caught off guard by the Doctor's two hearts. "Oh, baby, I'm beating out a SAMBA!"
* SpotTheImposter: Cassandra's ridiculous attempt at 21[-[[superscript:st]]-]-century Earth Cockney while in Rose's body, coupled with a knowledge of New Earth computer systems, gives her away early. You might also add her passionate snogging of the Doctor, but he seems to put that down to his own irresistible charm. But what ''really'' gives it away to the Doctor that Rose is not herself is how apathetic she is to the plight of the clone-people.
-->'''The Doctor:''' These people are dying, and ''Rose'' would ''care''.
* StableTimeLoop: Cassandra says Chip was made in the image of her favourite pattern — which came from the last person to tell her she was beautiful, inspiring said pattern. That last person is Cassandra herself in the pattern's body, by the by, who also inadvertently starts Cassandra's murderous vanity.
* StillGotIt: The Doctor believes Rose/Cassandra's random snogging him is due to his irresistible charm, which, naturally, carried over from his regeneration.
* StockFootage: The exterior shots of the lift car as Rose descends to the basement are reused footage from "[[Recap/DoctorWhoS27E1Rose Rose]]".
* SuddenlyShouting:
-->'''The Doctor:''' What's the turnover, hm? A thousand a day? Thousand the next? Thousand the next? How many thousands? For how many years? HOW MANY?
* SuicideDare: Not so much dare as attempted order. Both Rose and the Doctor take turns bellowing at Cassandra to get out of the other's body (and thus ultimately die without a host). They can't seem to fathom why it doesn't work. Left with the dilemma of her finding a willing host, the Doctor attempts to haggle by offering to keep her alive in a skin tank and take her to be tried for her crimes.
* SupermodelStrut: Cassandra tends to walk with a confident strut after possessing Rose in order to both [[DirtyOldWoman enjoy]] and [[TheTease take advantage of]] her [[ShowingOffTheNewBody new sex appeal]].[[note]]Creator/BilliePiper does this intentionally in order to emphasize Cassandra's haughtiness.[[/note]]
* SycophanticServant: Chip, despite being [[DirtyCoward left for dead rather apathetically by Cassandra]], dotingly serves her and cheerfully donates his body as a host (and thus facilitates his death), even scolding the Doctor for objecting.
* TakenForGranite: One of the diseases causes petrification.
* TakeThat: New Earth has a lot of themes that can be interpreted as criticism towards unjustified experimentation and capitalist exploitation. There are experiment subjects and even people who are manipulated as mere objects. There's the weak that get exploited so that the few can remain healthy, Cassandra's xenophobic views were left ambiguous in the past but over here she gets portrayed as something akin to a [[TheSocialDarwinist capitalist, white supremacist]], and there's people like her that are too selfish or apathetic like to try to change things until the Doctor shows everyone a better way.
* TheTease: The Doctor is briefly fooled by Cassandra into thinking that this strutting, flirtatious, cleavage-baring version of Rose who's just rejoined him in Ward 26 is merely his companion trying out a new persona, right before she snogs him like it's going out of style.
-->'''Rose/Cassandra''': Just larking about. New Earth...new me ''[puffs out her chest provocatively]''.
* TheTeaser: In the only series premiere in the RTD era to feature a cold-open, the episode's pre-credits sequence sees the new Doctor starting up the TARDIS for the first time, while Rose says her goodbyes to Jackie and Mickey once more. As they depart for new adventures, Rose asks the Doctor where they're going, and he answers: "Further than we've ever gone before..."
* TechnicallyLivingZombie: The zombies are artificially-grown humans who are carriers of every single known (non-zombie) [[ThePlague disease]] in the galaxy. They're actually intelligent and sentient, but seemingly too [[DesperatelyCravesAffection desperate for another human's touch, unaware of the consequences]], and/or driven by {{revenge}}, to care about the fact their touch fatally infects people with every disease in the world. They're ultimately rendered fully human when the amalgamate diseases they're carrying are simultaneously cured from their bodies.
* TechnoWizard: One of the clues that leads the Doctor to suspect Cassandra's impersonation of Rose, since she demonstrates advanced knowledge of computer systems billions of years ahead of her time and supplies an uncharacteristic amount of {{Technobabble}} to unlock the secret terminal entrance to the hospital's Intensive Care ward.
-->'''Cassandra/Rose:''' Why would they hide a whole department...? It's gotta be there somewhere. Search the subframe.\\
'''The Doctor:''' What if the subframe's locked?\\
'''Cassandra/Rose:''' [like it's obvious] Try the installation protocol.
* {{Telepathy}}: The Face of Boe has this ability, much to Cassandra's chagrin:
-->'''Face of Boe:''' ''[telepathically]'' There are better things to do today. Dying can wait.\\
'''Rose/Cassandra:''' Oh, I hate telepathy. Just what I need, a head full of Big Face.
* {{Teleportation}}: After assuring the Doctor he will tell him his secret on the third time they meet, the Face of Boe whisks himself away from the hospital seemingly through the power of his own mind.
* ThisIsGonnaSuck: Cassandra, upon realizing she's got to possess one of the infected humans so the Doctor can use his sonic screwdriver to help them escape:
-->'''Doctor/Cassandra''': Oh, I am so gonna regret this...
* TitleDrop:
-->'''The Doctor''': It's the year five billion and twenty-three, we're in the galaxy M87, and ''this''...this is New Earth.
* ThrillSeeker: Cassandra leans towards being an adrenaline-junkie in the episode, [[TheHedonist probably as a result of her hedonistic tendencies]], deciding to work with the Doctor despite Chip's warnings about the danger of it, mirking in excitement when they discover the secret rooms of the nuns and actually enjoying her role as the Doctor's companion not even bothering to reveal her facade until her coldness blows her cover.
* TouchOfDeath: The clone-people are infected with every disease known to the galaxy; some of them can kill in minutes. All of it is infectious. The Doctor inverts this trope by curing a bunch of them and sending them out to cure the rest by touching them.
* TokenEvilTeammate: For a short while, Cassandra becomes this to the Doctor. After her possession of Rose is discovered, her plans to blackmail the Sisterhood backfire and her new BodySurf habit forces her to confront some uncomfortable truths, she's eventually forced to fill the role of the Doctor's companion in Rose's absence. Before long they're FastRoping down a lift shaft and joining forces to cure the diseased, albeit Cassandra is doing so largely out of self-interest.
* TrojanHorse: [[MeaningfulName Cassandra]] uses Rose as this, [[FemmeFatale objectifying her looks in order to seduce the Doctor]].
* TrueBlueFemininity: Rose's zip-up blue jacket at the beginning of the story fits her honest, caring and gentle persona until she later gets possessed by Cassandra, who strips it off for the purple top she's wearing underneath because GracefulLadiesLikePurple.
* UndyingLoyalty: Chip is extremely faithful to his mistress Cassandra. How faithful? He volunteered for GrandTheftMe, even if it means dying for her.
* VainSorceress: Cassandra is interestingly enough a JustForFun/SciFiCounterpart. Her knowledge of technology and use of it to modify her looks and manipulate others can be seen as a parallel to her dwelling in dark magic, she has her own "Crystal Ball" and is obsessed with beauty. Her actions make her ironically less attractive at first, but in her new appearance she is more straightforwardly lustful of youth and body purity, causing her to [[DistractedByMyOwnSexy become enamoured with Rose and her new appearance]], so Cassandra is a mix of this and TheSocialDarwinist.
* TheVamp: Cassandra takes on this role after possessing Rose. Believing the Doctor can help her discover the secrets of the Sisterhood, she attempts to exploit his relationship with Rose by sexualizing Rose's appearance and trying to seduce him.
* VictoriasSecretCompartment: Pulled by Cassandra in Rose's body for a container of knockout gas.
* VillainNoLongerIdle: Whereas her immobile trampoline self-delegated everything to underlings in her [[Recap/DoctorWhoS27E2TheEndOfTheWorld previous appearance]], Cassandra is far more enterprising and resourceful this time round. Snatching Rose's body means she can investigate the secret goings-on in the hospital, blackmail the Sisters of Plenitude and exact her revenge on the Doctor by herself, though Chip warns her against it.
* VillainousBreakdown: Cassandra starts to cry when the Doctor demands she leave Rose's body for good, knowing this will result in her death. When she transfers herself into Chip, though, she finally seems ready to FaceDeathWithDignity.
* VillainousBSOD: Cassandra, after ending up in the body of one of the sick, discovers what it's like to be one of them.
-->'''Rose/Cassandra:''' Inside her head... they're so alone... they keep reaching out, just to hold us... all their lives and they've never been touched.
* VillainousCrush:
** Cassandra gains one towards the Doctor after possessing Rose, but the episode implies it might not be entirely out of her own free will. Her passionate canoodling session with the Doctor seems to be a case of her being sexually frustrated after living as a piece of skin for so long... but it could also be seen as her [[FusionDance gaining some of Rose's personality traits]] as a possible side-effect of the psychograft, including her -- Rose's -- secret crush on the Doctor. When Cassandra meets him in person as Rose, she's either so overwhelmed by her new feelings that she [[DirtyOldWoman just can't help herself]], or else is choosing to act on them where Rose would not. She also seems to enjoy being The Doctor's companion, [[ThrillSeeker smirking when they find the secret room of the nuns]] and doesn't bother revealing her facade either.
** She also seems to develop one towards Rose and her new self-image after possessing her, getting distracted for significant amounts of time checking herself out. Despite her classist hatred, Cassandra [[DirtyOldWoman is also clearly thrilled at the idea of having Rose's young and pure human body for herself]].
* VillainProtagonist: Cassandra ends up being the episode's main character. The Doctor provides the final solution to the narrative, while Rose spends most of the story [[GrandTheftMe as Cassandra's host]] and doesn't have much actual screen-time as herself. The episode expands on much more of her background in order to explain her villainous traits and she gets the most character development. Despite following her own evil plan and nearly succeeding, Cassandra's role as an antagonist still gets a lot less relevance than the Sisters of Plenitude. She becomes the [[NominalHero Nominal Hero]] of the story, assisting the Doctor in curing the Flesh, and her story arc ends with her accepting them as her "children" of sorts before deciding to accept her death for good. In contrast to her previous unethical [[ImmortalitySeeker ways of clinging to life]], Cassandra instead decides to move on after passing on a part of herself to the future, which is a much more "humane" way of coming to terms with death itself. It fits with the themes of the episode about what it means to be human and how she's gained that value back through her journey.
* VillainRespect:
** Cassandra has to admit the Doctor bested her last time and holds a grudging respect for his intellect, to the point that she refuses to work alone when Chip tells her he is too dangerous, thinking they have a better chance of finding the secrets of the Sisterhood together.
** Similarly, despite her disdain for Rose's [[LowerClassLout working-class background]], Cassandra agrees with Chip's praise of her beauty and sees Rose as a decent [[FantasticRacism pure-blooded host]], at least until [[EvilMakeover she can improve her looks through plastic surgery]] or find someone more sophisticated.
* TheVirus: The diseased clone-people try to make others sick, although it's not clear that a "second-generation" infectee would do the same.
* VoicesAreMental: {{Downplayed|Trope}}. When Lady Cassandra possesses Rose and the Doctor (constantly alternating between the two), she speaks with the host's voice but retains her posh accent. With Rose, this means that Creator/BilliePiper uses a slightly more arch variation of her native RP accent instead of the London accent she normally uses, while for the Doctor, Creator/DavidTennant speaks in a modified version of the Estuary English accent he adopted for the character.
* WardrobeFlawOfCharacterization: Rose's groomed, more confident look in this episode is ever-so-slightly undercut by the way the collar of her purple shirt is scruffily folded back over the top of her zip-up jacket, a reminder of the scrappy, streetwise girl she was in Series 1.
* WellIntentionedExtremist: The cat nuns, who use thousands and thousands of scratch-made humans and infect them with every disease known in the galaxy in order to manufacture fast and effective cures for diseases, where cures would normally take thousands of years to find. The episode itself plays with this, as Sister Jatt callously executes a test subject who has gained sentience and Matron Casp seems more angry at the Doctor for ruining the Sisters' reputation, and curses the humans for bringing so much illness with them. Novice Hame seems more upset about the people that will be infected if the clone-people escape, albeit because she (and the rest of the nuns) don't see the clones as real people.
* WeWillHavePerfectHealthInTheFuture: Discussed.
-->'''Rose:''' I thought this far in the future, they'd have cured everything.\\
'''The Doctor:''' The human race moves on, but so do the viruses. It's an ongoing war.
* WeWillMeetAgain: The Face of Boe leaves the Doctor with an assurance of this.
-->'''Face of Boe:''' We shall meet again, Doctor. [[Recap/DoctorWhoS29E3Gridlock For the third time. For the last time]], and the truth shall be told. Until that day... ''[teleports away]''
* WickedCultured: Subverted with Cassandra, who is notably far more familiar with advanced futuristic technology than Rose, but despite her millenia of experience she doesn't recognize Rose's Nokia phone and has to be told what it does when she thinks Rose's "rear bumper" is ringing. An originally scripted line had her commenting "It's so antique! What do I do...?", only reinforcing how such technology has become forgotten knowledge by the year five billion.
* WhatWouldXDo: Parodied; after possessing the Doctor's body, the clones burst into the room and Cassandra demands to know what the Doctor would do (the answer of course, provided by Rose, is [[RunOrDie get the hell out of there]]). She then demonstrates what the Doctor would ''not'' do by shoving Rose out of the way [[ItsAllAboutMe so she can go up the ladder first]].
* WhoEvenNeedsABrain: Cassandra's brain meat expires after she completes the psychograft transfer into Rose, but her mind survives, "safe and sound", in Rose's body.
* WineIsClassy: The Duke of Manhattan and Frau Clovis celebrate his miraculous recovery from Petrifold Regression with champagne, served by his personal butler. The Doctor is offered a glass, but declines.
* WolfInSheepsClothing: Once again, [[MeaningfulName Cassandra]] uses a [[TrojanHorse Trojan Horse]] tactic, this time [[EnemyWithin pretending to be Rose]] in order to find a way to regain her wealth and [[GrandTheftMe snatch Rose's body for good]].
* WoobieDestroyerOfWorlds: The clone-people are walking plagues, but all they want is for someone to help them and love them.
* WorthyOpponent:
** Cassandra respects the Doctor and his intellect to the point in which she chooses to work with him instead of alone despite Chip pointing out the danger of it.
** Cassandra feels this way towards Rose when it comes to embodying [[FantasticRacism her ideas of beauty and race]]. It's the reason why [[DirtyOldWoman she chooses her as her new vessel]].
* {{Yandere}}: Subverted, Rose (possessed by Cassandra) may count, since while a [[VillainousCrush part of her is lovestruck]] with the Doctor, [[BestServedCold the other part wants to kill him nastily]]. She is also prettier and more haughty about it than "cute". Cassandra herself may count depending on how much she liked her lovers before [[FemmeFatale her usual move on them]].
* YouHaveOutlivedYourUsefulness: Chip is callously left to die by Cassandra after he gets separated from her and the Doctor while running from the plague-carriers.
** Subverted at the end of the episode, since he survives, and Cassandra realizes she can use his body as an ideal substitute for possessing Rose.

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