The one where the Doctor has an in-joke with himself and Martha has a clone with a bald spot.
Written by Helen Raynor.
So the world's choking to death with Sontaran cloning gas spewing out of every car on the planet. UNIT gives the Doctor a gas mask (and ignores him when he quips "Are you my mummy?"). He hangs out with obvious-clone-Martha for a bit, because even though she's working for the Sontarans she happens to be doing exactly what he wants her to do: stop UNIT from launching a nuclear attack.
Rose very, very briefly shows up on a UNIT screen, screaming at the Doctor. He doesn't notice.
Luckily, the Doctor can whip up something that can burn all the gas, cleansing the air, using technology that has conveniently been developed by Rattigan's geniuses for when they were going to move to a new planet. He also, once again, decides to sacrifice himself, but Rattigan takes his place and, in a Heroic Sacrifice, blows up the whole Sontaran fleet with a Sontar-HA!
As the Doctor and Donna prepare to see Martha off, the TARDIS abruptly takes off of her own volition, to an unknown destination...
- Anger Born of Worry: After the Doctor's near-sacrifice, Martha immediately hugs him. Donna whacks him on the arm, then hugs him.
- Armour Is Useless: The Sontarans' armour seems mostly decorative, as UNIT mows them down when their firearms are working again. It might be that it's specifically designed to counter energy weapons, the same way that Kevlar is specifically designed to stop bullets, and less good against more primitive weapons like blades.
- Artistic License Gun Safety: The Doctor throwing Luke's gun across the room is incredibly dangerous. That is, assuming the gun is even loaded.
- Atmosphere Abuse: The Doctor sets it on fire!
- Atomic Hate: No Russia, for some reason. Even though North Korea gets in on the action!
- Authority Equals Asskicking: Colonel Mace can kill a Sontaran Commander Skorr, no less, who's an example in his own right in one shot without using the back of the neck weakness. No one else can do this. Oh, and he warns the Sontaran of his presence."You will face me, sir!"
- An Axe to Grind: When the Doctor and Donna are unable to free Wilfred from his car, Sylvia comes along with an axe and smashes the windscreen. She claims she has it in case of burglars.
- Badass Army:
- Subverted. The Sontarans appear to be one of these until UNIT overcomes their weapons being disabled and gives them the ass-kicking of the century. The Doctor had just introduced them as the greatest soldiers in the universe, too.note Despite all their talk of discipline they fight as individual warriors, and once UNIT gets around their advanced technology (a field that makes copper-jacketed bullets unfireable), they're immediately cut down by UNIT's organized fire-teams. It's stated that they could have easily destroyed Earth from orbit without much trouble, but on the ground UNIT is more than equal to the challenge, especially since the Sontarans aren't expecting any resistance and allow themselves to be caught off-guard.
- Played straight with UNIT, as once they find a way around the Sontarans' anti-gun field they proceed to mow down the Sontarans with ease.
- Bad Guys Do the Dirty Work: The Sontarans correctly deduce that the Doctor is bluffing when he threatens to blow up their ship, reasoning that he doesn't have it in him to kill them all. As it turns out, Luke does.
- Bizarre Alien Senses: The Doctor can tell that clone!Martha is a clone because of "reduced iris contraction", and a "thinning of the hair follicles on the left temple".
- Blue and Orange Morality: Commander Skorr seems genuinely pleased that Colonel Mace had the honour to demand he turn around before putting a few bullets into him, and compliments him on his martial virtue as he lays on the ground, dying.
- The Brigadier:
- Colonel Mace again carries on from the previous episode.
- Brigadier Sir Alistair Gordon Lethbridge-Stewart himself also gets a Shout-Out. The Doctor says that he wishes the Brigadier was here. Mace agrees, compliments him and says that he's "stranded in Peru".
- Chekhov's Gun: Chekhov's Hammer, in this case Donna uses the one the Doctor occasionally uses on the TARDIS console.
- Cliffhanger: As Martha's saying goodbye to the Doctor and Donna, the door slams shut and the TARDIS abruptly takes off of her own volition, startling everyone.
- Cloning Blues: Clone!Martha quickly falls into a downward spiral of it when Real!Martha's awakening cuts off her life support.
- Colonel Badass: Colonel Mace proves he's one not only by inspiring UNIT to put some steel-jacketed rounds in Sontaran heads, but he also double-taps Commander Skorr with a pistol this after Skorr easily took down two UNIT soldiers armed with automatic rifles, and Mace intentionally sacrifices the advantage of coming up behind him to look him in the eye.Colonel Mace: You will face me, sir!
- Continuity Nod:
- "Are you my mummy?"
- The Valiant returns from the end of series 3.
- And it's been fitted with Torchwood's Sunglider weapon from "The Christmas Invasion".
- The Doctor, who Donna can see and hear on a monitor, secretly communicates with her the same way he did with Mickey in a previous episode. He gets her attention by saying "noble", while with Mickey he repeatedly used the word "idiot" (which is what he frequently called him).
- The whole Brig-stranded-in-Peru thing harkens back to the classic run and The Sarah Jane Adventures, where it's a Running Gag for the Brig to be "stranded in Peru" when important things are happening with UNIT.
- Rattigan calls the planet he intends to colonize "Earth.2", similarly to how the Cybermen referred to themselves as "Human.2".
- Curb-Stomp Battle: The Sontarans find themselves on the receiving end of one this time once UNIT figures the Sontaran technology that stops their guns from firing. Once that happens, the aliens start getting mowed down.
- Cutting the Knot: While Donna and the Doctor try to fiddle with the car to unlock it, Donna's mother comes over and smashes the windscreen with an axe.
- Deadpan Snarker: Colonel Mace learns this (not saluting) is the best way to cope with the Doctor's constant snide comments.
- Deadly Gas: Downplayed the gas is harmful, but not fatal until it reaches a very high density. This is a hint that it's not meant to be a weapon, but something else.
- Defcon Five: Averted, the DEFCON status is used correctly. Nukes are ordered to be launched at Defcon 1.
- Doesn't Like Guns: The Doctor snatches Luke's gun out of his hand and throws it away without breaking his stride. "If I see one more gun..."
- Don't Make Me Destroy You: The Doctor puts his own life at risk to give the Sontarans a chance to walk away. They're far too egocentric to surrender and decide it'll be worth it if he gets blown up with them.
- Enemy Mine: The united nuclear response includes India, Pakistan, the USA, China and North Korea. (Oddly, not Russia.)
- Famous Last Words:
- Skorr: "Wonderful..."
- "Sontar. HAH!"
- Failed Attempt at Drama: The Doctor gives Donna her own TARDIS key, echoing Rose and Martha. "Quite a big moment, really." Donna suggests they celebrate after dealing with the poison gas.
- Fate Worse than Death: Luke's fellow students clearly consider his proposed "utopia" to be this; not even threatening them at gunpoint gets them to sign on.Luke: I designed a mating program. I planned the whole thing!
Student: Well then, shoot me. [she leaves, as do the others]
- Brilliant but unnoticeable:Donna: [to Martha, who's wearing the Doctor's coat over her hospital-type gown] You know, that coat sort of works.
Martha: Feel like a kid in my dad's clothes.
Donna: Oh, well if you're calling him dad youre definitely getting over him.
- For a fraction of a second, Rose Tyler appears on the screen of the TARDIS when the Doctor sends his message to the Sontarans.
- Brilliant but unnoticeable:
- Forever War: The Doctor reveals that the Sontaran-Rutan war has been going on for fifty thousand years.
- Freeze-Frame Bonus: Rose Tyler can briefly be seen on the TARDIS's screen, yelling the Doctor's name, before it switches to the UNIT control room.
- Fun with Acronyms: ATMOS, again.
- Gas Mask, Longcoat: The Doctor puts on a gas mask while wearing his Badass Longcoat.
- Genius Breeding Act: Luke tells his fellow Teen Geniuses about the one he has planned. They don't respond enthusiastically.
- Glory Seeker: The Sontarans would rather get blown up than let the Doctor win. In fact, getting blown up with the Doctor is even better! What a glorious death that would be!
- Grammar Nazi: Luke and the whole "'Atmos System' is redundant because the S stands for System" thing returns hilariously. When the Sontarans reveal that they'd have used Luke and his students as target practice once they'd outlived their usefulness, they don't actually make a priority of doing anything to the lone Luke... until he corrects them about that again. Then it's "EXECUTE HIM!"
- Gunship Rescue: "UNIT carrier ship Valiant reporting for duty, Doctor." Despite his usual dislike of weapons and soldiers, the Doctor is genuinely impressed, and, before he catches himself, excited. Cue Colonel Mace's pointed remark.Mace: Having fun, Doctor?
- HeelFace Turn: Rattigan rescues the Doctor from his own Heroic Suicide so he can finish off the Sontarans himself.
- He Had a Name: "He wasn't 'Greyhound 40', his name was Ross. Now listen to me, and GET THEM OUT OF THERE!"
- Heroic Sacrifice: Luke "does something clever" by swapping himself with the Doctor and blowing up the Sontarans and himself.Luke: Sontar-HA!
- "Hey, You!" Haymaker: Colonel Mace does this to Commander Skorr with his gun.Mace: You will face me, sir!
- Honour Before Reason: Both the Doctor and Colonel Mace.
- Mace challenging Commander Skorr rather than just double-tapping him from behind. Since Mace is a Colonel Badass, he still puts Skorr down."You will face me, sir!"
- The Doctor's doesn't quite go as well.Martha: Just send that thing up on its own. I don't know, put it on a delay!
The Doctor: I can't.
Donna: Why not?
The Doctor: I've gotta give them a choice.
- Mace challenging Commander Skorr rather than just double-tapping him from behind. Since Mace is a Colonel Badass, he still puts Skorr down.
- Hostile Terraforming: Weakened by their eternal war with another race of Scary Dogmatic Aliens, the Sontarans hatch an uncharacteristically circuitous plan to bathe the Earth in gas which is poisonous to native life but nutritious to themselves, so that they can use it to spawn more soldiers.
- Idiot Ball:
- Donna. Possibly justified because she is alone in a dangerous situation (and thus may not be thinking as clearly).Donna: [on phone to the Doctor, regarding the use of a door switch] But it's Sontaran-shaped, you need three fingers!
The Doctor: ... You've got three fingers.
Donna: Oh yeah!
- Despite knowing about the Sontarans' gun-blocking signal, the Doctor doesn't tell the Colonel, resulting in Ross' untimely demise.
- Donna. Possibly justified because she is alone in a dangerous situation (and thus may not be thinking as clearly).
- Informed Ability: The Sontarans being the "universe's greatest soldiers" when their tactics appear to mostly consist of walking forward and shooting people. Sure they mopped the floor with the UNIT forces in the first encounter, but once the humans got past the Sontarans' blatant cheating (a field which prevented their weapons from firing, making them incapable of even fighting back) they absolutely curb-stomped the "invincible" Sontarans. And unlike, say, Daleks with powerful shields, these guys get cut down by bullets pretty easily when their copper-expanding gimmick fails.
- Considering this is coming from a Technical Pacifist who views the word "soldier" as an insult, and that Sontarans are obviously a Martyrdom Culture that believes War Is Glorious, this actually may have been a bit of Fridge Brilliance. And it was stated several times throughout the episode that the Sontarans were holding back since they could have killed everyone easily, but needed the planet intact; and the Sontarans inside the factory were caught flat-footed, as they expected no resistance since the soldiers' weapons were disabled.
- Insufferable Genius: Luke Rattigan is revealed to be a Jerkass Woobie because of this. All he ever really wanted was to have some real friends who would praise him for his achievements, hence why he was so willing to work for the Sontarans, even hoping they'd adopt him into the fold, as it were. When they reveal he's disposable, he takes the Doctor's comment that he should do something clever with his life to its logical conclusion and decides to atone for his error by doing a Taking You with Me to the Sontaran mothership.
- In the Back: Colonel Mace defies it, but only just. Coming up behind Commander Skorr during the UNIT counterattack, he bellows, "You will face me, sir!" and then puts three bullets in Skorr's chest the second he turns around.
- Intelligence = Isolation: Invoked by Rattigan, who argues that he and his fellow geniuses have spent their lives being excluded and laughed at by other people, and thus deserve to live more than "those cattle". Unfortunately for him, no one else thinks that way: his fellow students turn out to be quite well-adjusted and just want to find their parents. Rattigan is reduced to impotently ranting that this "proves" he's cleverer than them.
- It Has Been an Honour: "Donna, thank you. For everything. Martha, you too. Oh, so many times. Luke, do something clever with your life."
- Just Between You and Me: Defied: "A general would be unwise to reveal his strategy to the opposing party."
- Kick the Dog: When Donna and Sylvia talk on the phone, Donna tries to reassure her mother that people are working on the gas problem. Sylvia just snidely asks how she'd know that.
- Leaning on the Fourth Wall: When the Doctor complains about being stuck on Earth like a human, he quickly apologizes. As he does that, he looks at the camera for long enough that this apology is more to the viewers than (evil) Martha.
- Martyrdom Culture: The Sontarans.The Doctor: General Staal, you know what this is. But there's one more option: you can go. Just leave. Sontaran High Command need never know what happened here.
Staal: Your stratagem would be wise if Sontarans feared death, but we do not.
- However, this doesn't stop them having an Oh, Crap! moment when Luke replaces the Doctor because they know that unlike the Doctor, he won't hesitate.
- Mauve Shirt: After spending 1.5 episodes as the Doctor's sidekick, Ross Jenkins is killed in battle. This is why the Doctor doesn't like guns!
- Monumental Damage: Though they aren't damaged, news reports show poison gas around the Hagia Sophia and the Sydney Opera House. Also, the ignition of the gas in the atmosphere sweeps over the Chrysler Building in New York.
- More Expendable Than You: Luke sacrifices himself in place of the Doctor to blow up the Sontaran ship.
- Mundane Solution: When they find out the Sontaran technobabble field affects the copper in their bullet casings, UNIT just switches to steel-cased ammo and goes to town.
- Never My Fault: Luke, pointing a gun at our heroes, demands they not tell anyone what he did. "It wasn't my fault, the Sontarans lied to me!" The Doctor snatches the gun and throws it away without slowing down.
- Newscaster Cameo: Newsreader and presenter Kirsty Wark.
- No Endor Holocaust: How the Doctor managed to ignite the lower level of the planet's atmosphere without frying or baking the people and living things on the planet underneath the global-scale explosion is anyone's guess. Or manages to avoid destroying it and/or the ozone layer.
- The Nose Knows: Clone!Martha apparently smells bad, but only the Doctor can tell.
- Not Herself: Martha. The Doctor suspects this almost immediately one of the first things he asks the clone is if she's called her family. "No, what for?" Also, she smells.
- Officer and a Gentleman: Colonel Mace, who on spotting Commander Skorr, barks "You will face me, sir!", and waits for him to turn (though only just) before shooting him.
- Oh, Crap!: The Sontarans, when they see that Rattigan has replaced the Doctor.
- Out-Gambitted: The clone!Martha prevents UNIT from launching nuclear weapons at the Sontarans, only to discover that's just what the Doctor wanted, having immediately recognized her as a fake.
- Out-of-Character Alert: Clone!Martha has the original's memories, but not her concern for her family. She also misses the Doctor going "Avanti" instead of "allons-y", and gives off several other tells to an alien with Hyper-Awareness.
- Pendulum War: The conflict. At first UNIT is routed because the Sontarans have made their weapons inoperable. When UNIT brings in new bullets that aren't affected by the Sontaran technology, they return the favour.
- Proud Warrior Race Guy:Skorr: [dying] Wonderful...
- Red Sky, Take Warning: This one is burning with a global fire.
- Redemption Equals Death: Luke Rattigan commits suicide, saves the Doctor, and destroys the aliens when he realizes how badly he screwed up.
- Redshirt Army: Subverted with the UNIT troops. Initially the Sontarans slaughter them with their Frickin' Laser Beams because they've used Technobabble to render UNIT's firearms inoperable. But UNIT just pulls out, switches ammunition, then goes back in and mops the floor with them.
- Rousing Speech:
- Mace gives one to his soldiers about how they're going show the aliens that they are not Puny Earthlings. The mocking laughter stops now! The result is a highly motivated fighting force.
- Rattigan attempts to give one to his Academy geniuses about how Earth doesn't appreciate them and how they can leave it behind to start again! The result is everyone walking out on him.
- Shut Up, Kirk!: A rare heroic example: "Thank you, Doctor, for your lack of faith, but unfortunately I've stopped listening." After two episodes of contempt and insults from the Doctor, whom he had treated with utter respect from the start, Colonel Mace finally stops listening and proceeds to prove the Doctor wrong and wipe the floor with the so-called "universe's greatest soldiers". However, the mothership would have wiped them out from space if it wasn't for a mixture of the Sontarans being Blood Knights and wanting to have fun on the ground, and the Doctor, so he was correct about them standing no chance against the Sontarans. Notably, while the Doctor never congratulates Mace on the bullets thing (though this being the Doctor he wouldn't) he flat-out congratulates Mace for the use of the Valiant, being genuinely impressed.
- Smooch of Victory: Captain Price plants one on Colonel Mace when the wave of fire caused by the atmospheric converter passes to reveal a clean blue sky. They then get right back to business.
- Soldier vs. Warrior: UNIT fights like soldiers in organized squads, the Sontarans fight like individual warriors and UNIT are much more mobile. The Sontarans didn't stand a chance.
- Squick: In-Universe, as disgusted as Rattigan's fellow students are by his plan to destroy the Earth and move the school off-planet, what ends up making them leave is that he planned a mating program for them. (What's worse is that you'd need about 200 people to repopulate humanity without a lot of incest, and there are nowhere near 200 students at Rattigan's academy.)
- Stuff Blowing Up: The Doctor lights the upper atmosphere on fire. If the crossed fingers and "Please, please..." muttering are any indicator, the Doctor wasn't sure it wouldn't destroy the Earth.
- Swap Teleportation: Luke Rattigan pulls a Redemption Equals Death by switching places with the Doctor using one of these, taking his place in the Suicide Mission to stop the Sontarans. This is how he chooses to interpret the Doctor's parting instruction to "Do something clever with your life."
- Taking You with Me: The Sontarans consider their deaths acceptable if they get to take the Doctor down with them. They have five seconds to reconsider when Luke takes his place.The Doctor: You'll die, Staal!
Staal: Knowing that you die, too.
- Tempting Fate: Martha really should have said her goodbyes and "I'm good here" stuff outside the TARDIS.
- World-Healing Wave: Setting the sky on fire to remove the poison.
- You Are Better Than You Think You Are: The Doctor to Donna when she thinks she can't be helpful.
- You Have Outlived Your Usefulness: The Sontarans execute the brainwashed human soldiers, and were planning to use Luke and his students as target practice.
- You Must Be Cold: The Doctor gives Martha his coat. It's a bit big for her, but Donna thinks it works.