[[quoteright:350:http://static.tvtropes.org/pmwiki/pub/images/casandra_7468.jpg]]
[[caption-width-right:350:[[SarcasmMode Pretty sight, ain't she?]]]]

->''"You lot, you spend all your time thinking about dying, like you're gonna get killed by eggs, or beef, or global warming, or asteroids. But you never take time to imagine the impossible. That perhaps you '''make it.''' Maybe you survive. This is the year 5.5/apple/26, five billion years in your future, and this is the day... Hold on... ''This'' is the day the sun expands. [[DissonantSerenity Welcome to the end of the world.]]"''
-->-- '''The Doctor'''

Rose expresses a wish to visit the future, and the Doctor cheerfully obliges... but scorns her idea of a mere hundred years in the future in favour of five ''billion'' years. Nothing succeeds like excess!

It's the year 5.5/Apple/26 when the Doctor and Rose materialise aboard Platform One, a cruciform space station orbiting a dying star. The star is, in fact, our sun; and in a few minutes, it will finally expand and consume the Earth. This is considered high entertainment in the future -- SnuffFilm writ large -- so there's a collection of the rich aboard the platform. The guests include a giant face in a jar called The Face of Boe (who will become important later); the last pure human, Lady Cassandra O'Brien.Δ17 (who will also become important later) and a group of tree people. One of them, Jabe, twigs (heh) to the Doctor's oddness, and persuades her PDA to identify his species.

The Doctor seems well at ease in this company, but Rose is completely at sea. She wanders off and has a few second thoughts about this adventure business, as she realises that she is five billion years in the future in the company of a manic alien.

Meanwhile, some serious weirdness is transpiring aboard the platform. Little spider robots are crawling all over the place, pulling fun pranks like lowering the space station's sun visors so as to give anyone unfortunate enough to be around a fatal suntan.

The Doctor rejoins Rose, and they watch doomed Earth spin. Rose anxiously presses the Doctor for more information on his people, homeworld, etc.; the Doctor snaps at her for excessive nosiness, gives her mobile an upgrade to make up for it, then goes off to explore the station. Rose calls her mom for a bit of reassurance. (Although the call accidentally overshoots a little, and reaches Jackie some time ''before'' Rose met the Doctor.)

After Rose insults Cassandra, the mysterious Adherents of the Repeated Meme place her in a room where another set of sun filters are descending. The Doctor saves her, but the door is stuck after being struck by high temperatures.

Investigating the air conditioning following a mysterious shaking in the space station, the Doctor finds one of the spiders. With the help of Jabe, the Doctor sends the spider back to its masters. The Doctor realises the Adherents of the Repeated Meme is just a meme, an idea, or in other words remote controlled robots. The actual culprit was Cassandra. She intended to create a hostage situation. She teleports away, causing her spiders, having infiltrated the station deep, to break the safety and the glass on the station's exterior to break.

The Doctor and Jabe rush to find the button to reset the computer, restoring the safety; the space station was manned entirely by computers, computers the spiders compromised, and the makers of the "unsinkable" space station didn't account for this. Jabe holds down the switch to slow the deadly pathway of fans so the Doctor can reach it. Unfortunately, she's made of wood, so she catches fire and dies, and the fans start moving quicker just as the Doctor's at the last one. The Doctor, concentrating, passes through and resets the computer, ordering it to reactivate the shields at the point of the Earth's destruction. Cassandra is returned thanks to the Doctor's ability to reverse the teleport with the feed that allowed her to teleport through the heat, and her body contorts and creaks, and eventually explodes.

Space station saved, the Doctor and Rose go out for chips. The Doctor confides that [[WhamLine his home planet is destroyed]], and that he's the LastOfHisKind. So that's why he's been a bit moody recently. Unfortunately, it'll take another ''four years'' before we find out [[Recap/DoctorWhoS30E17E18TheEndOfTime exactly what happened]], and another ''eight'' to find out [[Recap/DoctorWho50thASTheDayOfTheDoctor the circumstances]] that lead to what happened.
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!!Tropes:

* AbsoluteXenophobe: Lady Cassandra, who declares herself the last pure human, and considers anyone who's made modifications as half-breeds and freaks.
* AmazingTechnicolorPopulation: You've got humanoids colored shades of blue, tree blue, and pink.
* AmbiguousTimePeriod: Set in the far-future year [[AlternateCalendar "5.5/Apple/26"]]. This system of dating wouldn't be kept; sequels to this episode imply it took place in the year 5 billion.
* ArcWords: The Moxx of Balhoon discusses "the Bad Wolf scenario" with the Face of Boe.
* ArsonMurderAndJaywalking: This brief announcement at the beginning.
-->'''Announcement:''' Guests are reminded that Platform 1 forbids the use of weapons, teleportation, and religion.
* BewareTheNiceOnes: This is the first example in the new series that shows the Doctor is not a man you want to be on the bad side of.
* BrainInAJar: Cassandra's.
* CombatTentacles: Jabe retrieves one of the "peace" drones by extending a vine, then apologizes -- "I'm not supposed to show them in public."
* ContinuityNod: The Doctor makes reference to being on the ''Titanic'', which was established last episode.
* DarkLordOnLifeSupport: Lady Cassandra, who exists as a sheet of skin on a rack with her BrainInAJar underneath, and has to be moisturized frequently.
%%* DeathCourse
* DeadlyRotaryFan: The Doctor must [[DeathCourse navigate a series of these]] in order to reach an [[MalevolentArchitecture otherwise inaccessible]] switch.
* DepartmentofRedundancyDepartment / ShapedLikeItself: "They're just so alien. The aliens are so alien. You look at them... and they're alien."
* EarthShatteringKaboom: Subversion: Earth is destroyed on-screen, but [[InsignificantLittleBluePlanet nobody in that era makes a big deal out of it]]... because it's five billion years from now, Earth's destruction was long overdue anyway, and humanity has abandoned it long before.
* FantasticRacism: Cassandra towards "impure" humans, a very large category of life which she includes [[{{Irony}} Rose]] in. Interestingly, Rose's reaction to Cassandra isn't much different in turn.
* FutureImperfect:
** A jukebox is called an [=iPod=], and an ostrich is pretty much called a dragon.
** As well as Britney Spears' "Toxic" being referred to as "a traditional ballad".
** Not to mention the fact that "Tainted Love" by Soft Cell is listed as the original in the iPod's record changer. Their rendition is, in fact, a cover; the original was written by Ed Cobb and recorded by Gloria Jones in 1965.
* HeroicSacrifice: Jabe, who allows the station temperature on her side of the fans to incinerate her, while allowing the Doctor to override the fans on his side without getting immolated.
-->'''Jabe:''' Then stop wasting time, Time Lord.
* ImStandingRightHere: "Whatever I am, it must be invisible."
* InternalHomage: The destruction of Gallifrey, which the Doctor mentions here for the first time, was also a massive StoryArc in the ''Literature/EighthDoctorAdventures'' novels.
* {{Jaccuse}}: "The Adherents of the Repeated Meme: J'accuse!"
* NiceToTheWaiter: Rose is kind enough to give a drudge permission to speak (!).
* NoOSHACompliance: There are giant spinning fans blocking the way to the reset-the-computer button. There is a switch to slow the fans down but it will cause all the heat to move past the person holding the switch.
* ObviouslyEvil: Lady Cassandra
* OhCrap: Twice on Lady Cassandra, the first one was when she finds out the Doctor caught her, while she was in the middle of insulting the people she tried to kill, behind their backs, before she was teleported. The second one when she realizes she is without her moisturizing crew and is drying up.
* PlantAliens: "Representing the Forest of Cheem, we have... trees." Jabe is a direct descendant of the Tropical Rainforest.
* PrecisionFStrike:
** Surprisingly, Rose. When confronting Cassandra, she calls her a "''bitchy'' trampoline".
** While a mild version by most standards, this is also the first time that the Doctor has used profanity on screen.
* SceneryPorn: Not being familiar with running a sci-fi series, Russell T Davies spent a quite disproportionate amount of the series one budget on this episode. All the money is right up on screen, but later episodes did suffer a bit for it. [[TropesAreNotBad But it did help win over legions of both new and old fans]].
* SciFiWritersHaveNoSenseOfScale: It's strongly implied here, and shown in "New Earth", that humanity and its descendants still resemble humans, and that Cassandra only looks how she does through plastic surgery.
* ShoutOut: Before becoming a major part of the show's mythology, the Face of Boe was originally just a throwaway reference to an obscure narrative poem by Creator/RudyardKipling.[[note]]Specifically ''The Ballad of Boh Da Thone'', about a bandit/warlord who consistently avoids the British Army's attempts to capture and/or kill him only to be crushed to death when a fat ox driver he's trying to rob falls down off his cart on top him. Said ox driver then decapitates Boh's corpse and sends his head by parcel post as a gift to an acquaintance who was one of the aforementioned soldiers who'd tried to catch him.[[/note]]
* SoundtrackDissonance: "Toxic"
* StockEpisodeTitles: 31 uses.
* SupernaturalPhone: The Doctor upgrades Rose's phone.
* SuspiciouslyAproposMusic: Rose is handling her first trip into space and the future quite well -- until they fire up the "[=iPod=]" and it starts playing a song from her own time, and she suddenly gets a massive case of culture shock and runs out of the room. The song is "Tainted Love". Also serves as {{Foreshadowing}} for Cassandra's plan once the mastermind of the plot is revealed.
-->''Sometimes I feel I've got to\\
Run away\\
I've got to\\
Get away''
* ThisBananaIsArmed: Cassandra's "moisturizers" are packing acid in their spritzers, which she reveals after the Doctor fingers her for the murders.
* TranquilFury: The Doctor does this after Jabe dies and he saves the Platform, coldly transporting Cassandra back to the Platform and refusing to save her as she dries out.
* {{Transgender}}: Cassandra, considering she reveals that she was born a boy, but is still referred to as "lady".
* TranslatorMicrobes: Rose is confused by AliensSpeakingEnglish until the Doctor explains the "gift of the TARDIS". Funnily enough, she's not happy to hear how his time machine gets in her brain and changes what she hears.
* TrojanHorse: The metal "peace" gifts and the ostrich egg.
* TheXOfY: "The End of the World"
* UnsettlingGenderReveal: Cassandra reveals in a chat with Rose that "she" was born a boy on Earth; although, considering what Cassandra was, you have to wonder if all concept of gender has long since disappeared.
* WhamLine: The Doctor? The last of the Time Lords. Gallifrey? Gone.
* WhoNeedsTheirWholeBody: Certainly not Cassandra.

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