"Judoon platoon upon the moon!"A medical student called Martha Jones heads off to a normal day at work, and a strange man (the Doctor) comes up to her in the street, says "Like so!", and takes his tie off. Martha, only mildly perplexed, continues to the hospital, where she encounters the same man, calling himself "John Smith". He's been in the hospital all day and has no idea what she's talking about. To top it off, the mysterious John Smith has two hearts. Then it starts to rain upwards, and the hospital ends up on the moon. The Doctor decides that Martha, being unperplexed by his two hearts (unlike some companions) and not flipping out over being on the moon, is exactly the sort of person he could use for help, so he enlists her in the task of saving the hospital.Meanwhile, a herd of rhino-alien-police (Judoon) enter the hospital and begin to methodically search it for alien life, so the Doctor needs to find the malicious alien and keep himself out of rhino hands, all before the hospital's supply of oxygen runs out.The alien in question is an old granny, a humanoid plasmavore, who is wanted for murder. She drains the head of the hospital, then fools a Judoon scan because the blood makes her read as human. (And, to distract the rhinos for a while, the Doctor puts some of his own alien bio-bits on Martha by snogging her. No complaints from Martha.) Anyway, Granny has devised a plan to save herself that will kill the human population (the half facing the moon, anyway). She imparts this plan in detail to mild-mannered "John Smith" and then drinks his blood.Martha finds the plasmavore just as she drains the Doctor dry, which, unbeknownst to her, renders her decidedly alien on any bio-scan. The Rhinos kill the plasmavore and Martha revives the Doctor, just in time for him to reverse the doomsday CT scan and save humanity. In return for saving his life, the Doctor offers Martha a quick tour of the galaxy in his TARDIS. She refuses at first, but then, in response to her question of how he would prove that the TARDIS can travel through time, he steps into the TARDIS, disappears, and reappears with his tie off. See first sentence.The Doctor promises her one little trip, just for fun, and they awkwardly agree that she's not there to replace Rose. Also, Martha's only attracted to humans. With those negotiations over with, they're on their way.
— The Doctor
- Alliterative Name: The plasmavore chose an alliterative alias Florence Finnigan.
- Almost Out of Oxygen: The force-field keeps the air in, but it starts running out quickly. Thankfully, the Judoon aren't completely merciless and teleport the hospital back once they're done.
- Arc Words: There's "Vote Saxon" signs in the alley at the end, and Mr. Saxon gets name-dropped.
- Assimilation Backfire: Finnegan drinks human blood so the Judoon would think she is a human when bio-scanned. The Doctor tricks her into drinking his blood, thus making her look like an alien through the bio-scanner, albeit different from what she actually is.
- Bigger on the Inside: Can't be an official Companion if you don't mention it. Complete with the Doctor mockingly mouthing along when Martha says it.
- Brick Joke:
- Oh, so that's why he said "Like so!"
- The Doctor squeeing over the hospital having "a little shop!"
- Comically Missing the Point: The Doctor has just absorbed a lethal-to-humans dose of radiation and is trying to expel it via his foot into his shoe.The Doctor: Ow, ow, itchy, itchy, itchy... (shakes foot wildly, hopping around on one foot, before pulling his shoe off and binning it triumphantly)
Martha: You're completely mad.
The Doctor: You're right. I look daft with one shoe. (pulls other shoe off) Barefoot on the moon!
- CPR (Clean, Pretty, Reliable): Apparently CPR will fix clinical death brought on by blood loss in non-humans. Considering how little we know abound Time Lord biology, this could be true.
- Dies Wide Shut: Dr. Stoker, after the Plasmavore drains his blood. Martha closes his eyes for him.
- Disproportionate Retribution:
- As Oliver Morgenstern is telling terrified patients to cooperate with the Judoon as they scan everyone looking for the Plasmavore, one patient grabs a vase and smashes it over another Judoon.Judoon Captain: Witness: a crime. Charge: physical assault. Plea: Guilty. Sentence: execution. (vaporises the man on the spot)Oliver Morgenstern: You didn't have to do that.Judoon Captain: Justice is swift.
- The Doctor is in a bit of a rush to get to the Plasmavore before the Judoons find her, because he knows that the Judoons will execute everyone in the hospital for harboring a fugitive if they find her first.
- As Oliver Morgenstern is telling terrified patients to cooperate with the Judoon as they scan everyone looking for the Plasmavore, one patient grabs a vase and smashes it over another Judoon.
- Eat Me: The Doctor goads the Plasmavore into eating him to expose her.
- Genre Savvy: Martha seems to find the sci-fi elements of the story a lot easier to accept than Rose or Donna did, partly because she's aware of the various current-day stories from the first two series. (Also, the audience was a lot more comfortable with it all by this point, so there wasn't as much need for the Audience Surrogate to be mystified.)
- Getting Crap Past the Radar: "It's a Slab, basic slave drone. Solid leather, all the way through. Someone has got one hell of a fetish."
- Have We Met Yet?: Martha recognizes the Doctor in the hospital, but he has no idea what she's referring to until the end of the episode when he does his "cheap trick".
- Hell-Bent for Leather:
- Parodied with the Slabs, androids composed entirely of leather, because of someone's fetish.
- Played more straight with the Judoon who are very dangerous.
- Hollywood Midlife Crisis: Clive Jones seems to be in the middle of one. He's about to turn 50, recently-divorced, and sporting a brand new car and a 21-year-old Caucasian girlfriend the script compares to a Big Brother eviction night.
- Human Aliens: Florence appears to be one, but that may just be a result of her disguise method. The Doctor of course is one, and this is used as a plot point when Florence is tricked into using his blood for her disguise.
- Impostor Exposing Test: The Judoon have scanners which can distinguish humans from non-humans, which they try to use to find a plasmavore criminal hiding in a hospital. The plasmavore is able to change its physiology by drinking blood, and tries to use that to beat the test; however, the Doctor tricks it into feeding on him. Since he's an alien, the scanners identify the plasmavore as non-human and kill it.
- Improbable Weapon User:
- Florence Finnigan's method of sucking blood is to use a bendy straw!
- Florence Finnigan uses an MRI machine which will fry the half of the Earth facing the moon.
- The Doctor kills a Slab with an X-ray machine by increasing the radiation output to fatal levels.
- Judge, Jury, and Executioner: The Judoon do this role when one guy tries assaulting one of them with a vase; "Justice is swift."
- Karma Houdini: Sure, the Judoon were polite enough to send the hospital back to Earth when they were done with it, and give Martha "compensation" but they murdered a man acting in perceived self-defense and nearly killed everyone else from oxygen starvation... and if the Doctor hadn't deactivated the MRI, it would have flash-fried everyone on Earth.
- Loophole Abuse: The Judoon have no juristriction on Earth.....so they transport the Hospital to the Moon instead.
- Meaningful Echo: Martha Jones is exuding so much calm confidence that she promises the Doctor that she will get him home. These are usually the Doctor's words; he looks slightly non-plussed.Martha: I promise you, Mr Smith, we'll find a way out.
- Meaningful Name: There's a "Dr. Stoker", who's the first on-screen victim of the blood-sucking Plasmavore.
- Midlife Crisis Car: Rusty's script describes Clive's car as "very much midlife crisis".
- Mundane Utility: "Crossing into established time streams is strictly forbidden. Except for cheap tricks."
- Noodle Incident:The Doctor: It's a screwdriver and it's... sonic.
Martha: What else have you got? Laser spanner?
The Doctor: I did, but it was stolen by Emmeline Pankhurst. Cheeky woman.
- Obfuscating Stupidity: The Doctor passes himself off as a postman while talking to Florence.
- Personal Raincloud: Referenced — the cloud over the hospital, just before the teleport, is compared to one by Martha's sister, like something straight out of the cartoons.
- Police Are Useless: The Judoon find and kill Florence right around the same time they discover she has turned an MRI machine into a weapon that will ravage half of the Earth. They state that the Earth is not within their jurisdiction (which is why they took the whole hospital to the Moon in the first place), and and announce their withdrawal. To make things worse, they don't seem to have known the MRI was disabled before returning the hospital to Earth, which would have in fact made the damage caused by it even worse.
- Recycled In Space: The Tenth Doctor plays with this trope:The Doctor: Have you seen?! There are these things, these great big space Rhino things, I mean, Rhinos from space, and we're on the moon! Big space Rhinos, with guns! ON THE MOON!
- Retirony: Dr. Stoker says he was planning to go on for two more years and then retire to Florida. Then he cements his fate with a version of the Fatal Family Photo, saying that he has a daughter still attending university.
- Rhymes on a Dime: Gotta love that "Judoon platoon upon the moon" joke. Played for Laughs when you realise they put that line in because when David Tennant pronounces "oon", he tends to get a bad case of Ooh, Me Accent's Slipping.
- Sad Clown: "You're quite a funny man — and yet, I think, laughing on purpose at the darkness. Time you had some peace."
- Shout-Out: The plasmavore uses a bendy straw to suck blood, much like how the Yugopotamians use bendy straws to feast on human brains.
- Stable Time Loop: Martha telling the Doctor how to prove he's a time traveller leads to him performing the "cheap trick" which is how she first met him.
- Steal the Surroundings: An entire building was transported to the moon so the Monster of the Week can locate a single person without them being able to escape.
- Suspiciously Specific Denial: You are not a Replacement Goldfish, Martha Jones!
- Thanatos Gambit: The Doctor allows the Plasmavore to feed on him so that she will register as an alien to the Judoon's scanners.
- The Unmasqued World: After the Slitheen, Sycorax and Cybermen, Martha takes being zapped to the moon in stride.
- Wham Line: A sneaky one when Martha asks the Doctor if he's got a brother, and he replies — "No, not anymore; just me." The Doctor's brother, Braxiatel, is a major character in the Doctor Who Expanded Universe stories (specifically in the Bernice Summerfield stories and in the Gallifrey audios) taking place before the end of the Time War.
- Would Hurt a Child: The Plasmavore is wanted by the Judoon for the murder of the Child-Princess of Patrovolt Regency Nine. She insists the kid had it coming just for being cute.Florence: Oh, those blonde curls and that simpering voice. She was just begging for the bite of a Plasmavore!
- You Are Who You Eat: The Plasmavore can shift their biology to whatever they drink from.