Carmen:No, but you be careful. Because your song is ending, sir.
The Doctor: What do you mean?
Carmen: It is returning. It is returning through the dark. And then, Doctor? Oh, but then... He will knock four times.A light-hearted Breather Episode with very little drama, written as a contrast to "Midnight".It's Easter. The Doctor has parked the TARDIS in the Buckingham Palace gardens ("she doesn't mind") and takes a bus trip around London. He tries to make small talk with Classy Cat-Burglar Lady Christina, who's escaping from a heist and who's convinced that the Doctor's just a rambling hobo. However, their conversation is short-lived as the bus takes an impromptu ride through a wormhole, taking the Doctor, Christina and the rest of the passengers with it.It turns out that the group have landed on San Helios, a desert-like planet with next to no life (except for some equally stranded Insectoid Aliens). The group have no way of leaving the wormhole — as the bus driver unfortunately proves — and there is a Horde of Alien Locusts on the horizon. Also, the passengers are getting suspicious of the Doctor, and he realises he's in danger of reliving some painful memories.However, it's the Doctor's lucky day: everyone, including the local merchant aliens, ends up trusting him. And instead of trying to save the day all by himself, he just quickly gets UNIT on the phone to deal with things back on Earth. Captain Erisa Magambo is honoured to talk to the Doctor. She hands the phone to Adorkable UNIT scientist Dr Malcolm Taylor (played by Lee Evans), who squees and squees when he finally gets to talk to his hero.The Doctor and Christina are forced to work together with the passengers to fight the hungry alien swarm that destroyed San Helios. The creatures are making a beeline for the wormhole that they created. Using Christina's Classy Cat-Burglar skills and Malcolm's brilliance, the bus is turned into a flying bus, and the Doctor saves the day. Captain Magambo thanks the Doctor, Malcolm glomps him and tells him "I LOVE YOU" about a dozen times over, and the TARDIS is neatly delivered by UNIT. Christina even manages to snog the Doctor, although he refuses to take her with him as his next companion, no matter how much she begs. He's lost too many friends recently. He does, however, sneakily destroy her handcuffs when she's arrested about five seconds later, and she climbs into the bus and flies off.Unfortunately, this story just won't allow the Tenth Doctor to catch a well-deserved break. After being fairly ebullient, it moves back into the realm of dramatic tension and seriousness for one moment. And in that brief pause, it serves up one hell of a Wham Line, delivered by resident psychic Carmen... the Tenth Doctor is going to die... very soon...200th serial of the series. Written by Russell T Davies and Gareth Roberts and based very loosely on Roberts's Doctor Who New Adventures novel The Highest Science; really they just took the striking image of a tube train crashing on an alien planet. And then made it a bus instead.
— Carmen, giving the Doctor a prophecy so chilling you can feel the Cerebus Syndrome hit from a mile away.
- Action Prologue: Christina's heist.
- Admiring the Abomination: Earns a What the Hell, Hero? from Christina, although she immediately admits that she's impressed too.
- Adorkable: Malcolm
- Aristocrats Are Evil: Subverted; Lady Christina is a thief, but she doesn't really fall in the "evil" category.
- Bavarian Fire Drill: Lady Christina immediately takes charge of the situation after the bus ends up on San Helios, and starts issuing orders to everyone during the initial confusion. Such tactics are Emergency Response 101 in Real Life. She immediately puts the Doctor in control once everyone has calmed down.
- Big Red Button: Turns off the security grid on the Tritovore's crystal shaft.
- Bilingual Bonus: Christina's response to the Doctor's catchprase.Doctor: Allons-y! (Let's go!)
Christina: Oui, mais pas si nous allons vers un cauchemar! (Yes, but not if we go towards a nightmare!)
- Bilingual Dialogue: The Doctor speaks insect click language with the Tritovores. Once the Tritovores employ their one-way telepathic translators, the Doctor uses English and they continue in their language.
- Breather Episode: Openly marketed as a last bit of fun for the Tenth Doctor.
- Buffy Speak:Christina: How does a crystal drive a bus?
Doctor: In a... super clever... outer-spacey way, just — trust me.
- Bus Full of Innocents: And one not-so-innocent master-thief.
- The prophecy in this special saying that the Doctor's song will be ending soon echoes the Ood's words from the end of "Planet of the Ood".
- The Doctor refers to Donna when Christina calls him "Spaceman".The Doctor: I had this friend, once. She called me "Spaceman".
- Caper Rationalization: Subverted. Christina claims that her father lost the family fortune when Iceland's banks crashed. The Doctor isn't fooled, pointing out that if she were short of cash, she'd be robbing banks - stealing from museums is "a lifestyle."
- Car Fu: With a flying bus.
- Chekhov's Gun: The Chalice of King Athelstan.
- Chekhov's Skill: Christina's rope-descending thing.
- Classy Cat-Burglar: Christina
- Continuity Nod:
Malcolm: The Doctor! Cor blimey. I can't believe I'm actually speaking to you. I mean, I've read all the files.
- The Doctor makes a reference to "Midnight":The Doctor: Humans on buses, always blaming me.
- Referencing this exchange between Malcolm and The Doctor.
Doctor: Really? What was your favourite, the giant robot?
- The Doctor makes a reference to "Midnight":
- Death by Materialism: The only human character to die is the bus driver, who, at the beginning of the episode, accepted a bribe to help a criminal escape a police cordon. (He accepted her diamond earrings in lieu of a valid ticket.) The criminal herself, whose motivation is explicitly stated to be non-materialistic love of adventure, survives.
- Development Gag: Lady Christina is very similar to what has been publicly revealed about a character who would have replaced Ace as companion, had there been a twenty-seventh season of the original show.
- Extreme Omnivore: The Swarm.
- Fake-Out Opening: The prologue looks like some exciting heist story and not at all like a Doctor Who episode. You could believe you got the wrong series until the Doctor boards the bus.
- Fanboy: Malcolm practically creams himself when the call from the Doctor comes. The Doctor is... put off, but not too much.
- Fingerless Gloves: Malcolm
- Flying Car: Flying bus.
- This is the first time in the revival that the Doctor admits he stole the TARDIS. After years of the Doctor acting nostalgic about Gallifrey due to being the Last of His Kind, RTD needed to re-establish that he didn't always agree with the other Time Lords. It's about to become very important...
- Virtually everything Carmen says.
- For Inconvenience, Press "1": The UNIT helpline.Phone: This is the Unified Intelligence Taskforce. Please select one of the following four options. If you want to report a UFO sighting, press one...
The Doctor: Aw, I hate these things.
Angela: No, if you keep your finger pressed on 0, you get through to a real person. Saw that on Watchdog.
- Genre Blind: Lady Christina does not include nigh-invisible forcefields as something she should watch out for when boldly dropping down a deep shaft to retrieve a MacGuffin. Fortunately, the Doctor stops her just short of a messy death.
- Ghost Planet: San Helios
- Godly Sidestep: The Doctor knows the true story of Easter. Right after he says "What really happened was—", he gets cut off and forgets what he was talking about.
- Go Through Me: Malcolm figures out how to close the wormhole, and plans to do so as soon as the Doctor (pursued by a Swarm Of Alien Locusts) makes it through. Captain Magambo orders him to close it immediately in order to prevent any of the voracious aliens from getting to Earth. Despite being held at gunpoint, Malcolm refuses to budge.
- The Guards Must Be Crazy: The security at the museum includes armed guards (when even the police don't carry firearms in the UK) and a fancy laser grid from which they all face away. It has less functionality than a glass case — the latter has a top for one thing.
- Hollywood Nerd: Malcolm is a Type 1.
- Horde of Alien Locusts
- Human Aliens: Lampshaded:Christina: You look human.
The Doctor: You look Time Lord.
- I Lied: Christina, right before kissing the Doctor.Christina: Remember when I said I hated you? I was lying.
- Immune to Bullets: Averted and Lampshaded. More Dakka returns as UNIT's SOP.Magambo: At last, guns that work!
- Insectoid Aliens: The Tritovores.
- Inspector Javert: McMillan definitely comes across as obsessed with arresting Christina.
- Ironic Echo: The Doctor and Malcolm Taylor each say "He hung up on me." and "Not now, I'm busy!" at different points.
- Is This Thing Still On?: When Captain Magambo and Malcolm gush over the fact they're actually speaking to the Doctor on the phone.Magambo: We all want to meet him one day, but we all know what that day will bring.
The Doctor: I can hear hear everything you're saying!
- Lady of Adventure: Lady Christina de Souza
- Lampshade Hanging: The Doctor points out how uncommon it is for him to arrive on Earth during Easter time, which lampshades that there are no Easter specials compared to the annual Christmas specials.
- Language of Truth: The Tritovores use telepathic translators, which can apparently discern truth from lies.
- Meaningful Name:
- The Bus is labelled 200, due to it being the 200th serial.
- San Helios ("Saint of the Sun") could be considered one, having a double meaning due to the planet having three Suns and (having had) an abundance of Temples.
- "Mission: Impossible" Cable Drop: Christina steals the chalice in the prologue. And then she uses the same skill to retrieve the antigravity clamps in the Tritovore ship.
- Mood Whiplash: Everyone's gotten back to Earth, everyone's happy, Christina's avoiding jail, and then the Doctor is told his song is ending. The jubilant music stops dead, replaced with something much more ominous.
- Mundane Utility:
- Carmen uses her psychic gift of precognition to play the Lottery and win £10 twice a week, every week.
- The Doctor uses his psychic paper to get on the bus in lieu of an Oyster Card.
- Mythology Gag: The flying red double-deck bus is meant to resemble Iris Wildthyme's TARDIS.
- Not So Different: The Doctor admits as such when he realises Christina is a thief.Christina: I take it you disapprove?
The Doctor: Absolutely! (pauses) Except... that little blue box... I stole it. From my own people.
Christina: Good boy! You were right, we're quite a team.
- Nightmare Fetishist: The Doctor can't stop himself from admiring the swarm's "perfect design", even though they've already wiped out at least one planet and are threatening to do the same to Earth. "Worse it gets, the more I love it."
- Psychic Powers: Carmen.
- Put on a Bus: A literal example! At the end of the episode, Lady Christina escapes from the police by flying off in the bus, and the character has not been seen since.
- Real Life Writes the Plot: The bus that was being shipped from Cardiff to Dubai was being unloaded at Dubai when someone dropped a cargo container on it. The damage was incorporated into the plot.
- Redshirt: The driver. The Doctor just saying they couldn't go back through the wormhole unprotected wouldn't have the same impact.
- Refused by the Call: After they return through the wormhole, Christina wants to join the Doctor for more adventures. He flatly refuses, and won't even give her a peek inside the TARDIS.
- Rule of Cool: Necessary for a Breather Episode. Flying alien stingrays! In a desert! A bus flying through London!
- Running Gag: The Doctor still doesn't like it when UNIT salutes him.
- Sequel Hook: "He is coming. He will knock four times."
- The number of the bus, 200, reflects the fact that this is the 200th Doctor Who story, counting "Trial of a Time Lord" as one story and the last three episodes of Season 29 as one as well.
- Malcolm's unit of measurement for four-dimensional phenomena is named in honour of Bernard Quatermass — David Tennant starred in the 2005 remake of The Quatermass Experiment.
- The world on which the bus lands is San Helios, which orbits three suns, similar to the Elite homeworld of Sanghelios, which also orbits three suns. And both stories begin when a human vehicle crash-lands on a strange world.
- Spy Catsuit: A pretty realistic example, because Lady Christina's outfit is not a catsuit, in fact, but black leggings, a black shirt and boots.
- Stripped to the Bone: The bus driver on trying to cross back the vortex.
- Too Dumb to Live: The bus driver, in an unfortunate side-effect of the Real Life Writes the Plot entry above. Since the bus originally wasn't supposed to be damaged by its trip through the wormhole, it makes sense that the driver would think he could walk back through it himself. Instead, we have him happily walking into an anomaly which has just ripped most of the top deck away from his bus, and being surprised when the flesh is seared from his bones.
- Vagueness Is Coming: Carmen's warning, but it's still enough to terrify the Doctor.
- Wham Line: "It is returning, returning through the dark."
- What Measure Is a Non-Human?: The Tritovores, poor things. Although it crosses with Too Dumb to Live and Honor Before Reason.
- The X of Y: "Planet of the Dead"
- Your Days Are Numbered: "Your song is ending, sir."