The one where Sarah doesn't like ginger pop.
The TARDIS lands in a typical English village that Sarah recognises as Devesham, home of the British Space Defence Station. However, it soon becomes obvious that things are not all as they should be, and the Doctor and Sarah realise that the village is a replica populated with androids.
An alien race — the Kraals — are aided by a brainwashed human astronaut, Guy Crayford, and have built the replica to rehearse for an invasion of the Earth. Styggron, a Kraal scientist, has perfected a lethal virus and plans to use his androids to disseminate it around the world, paving the way for the Kraal fleet.
Crayford, whose rocket had been damaged and who was rescued by the Kraals, returns to a hero's welcome. But with the Brigadier off in Geneva, no-one at UNIT believes the Doctor when he tells tall stories of android replicas — which now include himself, Harry and RSM Benton. The Doctor manages to use the radio equipment at the base to jam the android control signal and stop Styggron releasing the virus. He then uses his own android replica to fight Styggron, who infects himself with the virus in the process and is killed.
- All There in the Script: According to the script, Corporal Adams' first name is Richard.
- Arm Cannon: See quote at the top of the page.
- Back from the Dead: One of the many clues that something is terribly, terribly wrong in town is the fact the Doctor and Sarah see Corporal Adams up and about... despite him having just run off of a cliff earlier and had no pulse when they checked him.
- Bond Villain Stupidity: Styggron on at least two occasions.
- The Bus Came Back: Harry Sullivan and Sergeant Benton make their final appearances in Doctor Who.
- Chromosome Casting: Sarah is the only female character in the story.
- Complexity Addiction: Styggron might have actually conquered Earth had he just sprayed the planet with the impossibly deadly poison that would certainly have killed every human on Earth, rather than spend so much of his time dicking around with robot doubles, Gaslighting spacemen, and building hyper-realistic training simulations where the pubs are kept fully stocked up with ale but every day on the calendar reads the same date.
- Deadpan Snarker:
Doctor: "Don't go. Stay, then we can all go together!"
- The Doctor gets off a good one when tied to a post and left next to a bomb.
- Sarah herself gets a good one in the pub, when talking to the android Adams, telling him to make sure he doesn't fall.
- Differently Dressed Duplicates: Androids impersonate the Doctor and Sarah in each other's presence on two separate occasions. The Doctor realizes that the Sarah duplicate is not real because she was wearing a scarf that the real Sarah lost.
- Death Glare: Android Doctor has a terrifying one when Android Bentor shoots him, thinking he was the Doctor.
- Distressed Dude: Sarah busts the Doctor out of his cell."This time I'm saving you!"
- Does Not Like Spam: Sarah Jane apparently hates ginger pop. It's how the Doctor recognizes her ginger pop-drinking android impostor.
- Evil Knockoff
- Evil Redhead: The android Adams. The real one, though, being a dutiful UNIT soldier, is a good redhead.
- Eyepatch of Power: Crayford wears one. It later turns out he doesn't need it.
- Family-Unfriendly Violence: Sarah Jane's face falls off, revealing a terrifying robot face with protruding eyeballs. Robert Holmes famously received a letter about this from an eight-year-old complaining it was too scary (a Dramatic Reading of which is included as a DVD special feature).
- The Future: After many stories in which the original idea of the UNIT era being in the near future had been almost forgotten, the last but one of the 1970s UNIT stories fully revives it, being set in a world where the UK has a major functioning space programme, "freighter" flights out as far as the asteroid belt are routine, and crewed exploration journeys have reached Saturn at least.
- Gambit Roulette: Styggron's plot is almost as ludicrous as the way he goes about executing it. The DVD production note subtitles helpfully point out all of the holes in his plan and all the baffling and counter-intuitive moves he makes. Most fanon and Expanded Universe suggests Styggron didn't even understand his own plan.
- High-Voltage Death: Sarah busts out of her cell by taking a cable, waiting for Android!Adams to come in, and then frying him with it. He explodes quite spectacularly.
- Hoist by His Own Petard: Styggron ends up getting killed by the virus he intended to infect humanity with.
- Impersonating the Evil Twin: The Doctor pretends to be his android double and successfully fools the other androids. He also succeeds in reprogramming his double to assist him, a fact which is only revealed after the double has done a Heroic Sacrifice in front of his horrified companion.
- Large Ham: Two Tom Bakers? It's amazing any scenery was left.
- Styggron has his moments, too.
- Like an Old Married Couple: Styggron and Chedaki, full stop.
- Literal Cliffhanger: When Sarah Jane and the Doctor are fleeing from the androids, she ends up falling and dangling off of a cliff.
- Meaningful Echo: "Don't be a fool, Benton, I'm one of you." First said by the real Doctor when he bluffs the androids, then by the Android Doctor himself.
- Noisy Robots: Generally averted, since the androids are intended to be perfect replacements. The only one who does make any of the typical mechanical whirring and clanking noises is the malfunctioning Adams (the UNIT soldier who does the really spectacular cliff dive), and that's only because there's something wrong with him.
- Not Herself: Sarah Jane apparently hates ginger pop. It's how the Doctor recognizes her ginger pop-drinking android impostor.
- Obvious Second Choice: It's pretty obvious that Col. Faraday was supposed to be the Brigadier.
- Obvious Stunt Double: The Doctor's robot duplicate is clearly a double with a highly Off-Model wig.
- Only a Flesh Wound: The Android!Doctor shoots Grierson, but it only seems to hurt him in his arm/shoulder area.
- Out-of-Character Moment: The Doctor realizes Sarah Jane has been replaced when the android accepts the ginger pop he offers her, because he knows she hates ginger pop. In fact he figures it out the moment he sees her, because, as he put it, "The real Sarah wasn't wearing a scarf." Him giving her ginger pop is just his way of checking to make sure he's right.
- Platonic Cave: The fake Earth.
- Pseudo Crisis: Episode Three has a cliffhanger where Sarah and the Doctor are getting blasted off into space and are overcome by the G-force... and then they escape the planet's gravity and everything's fine. Particularly sloppy since the scene immediately after this shows a pod opening to reveal an evil robot Doctor.
- Real Life Writes the Plot: When a pack of dogs have his scent, the Doctor has to jump into a small pond to evade them. Tom Baker performed the stunt for real while on location, and he got a minor throat infection from accidentally taking in some of the water. It wasn't too serious, but his voice sounds a little bit off thereafter.
- Redemption Equals Death: Crayford.
- Ridiculously Human Robot
- Robot Me: The android replicas include the main characters.
- Robotic Reveal: When the Doctor works out android "Sarah" isn't the real one, she pulls a gun on him. He tackles her to the ground, and her face comes off, revealing the inner workings of the android. (See image).
- Servile Snarker: Chedaki is an evil version.
- The Doctor says to Sarah, "Listen, once upon a time, there were three sisters, and they lived in the bottom of a treacle well. Their names are Olga, Masha, and Irina." This is a mash-up of lines from Alice in Wonderland and Anton Chekhov's Tre sestry.
- The Doctor says, "The best laid schemes of mice and Kraals gang aft agley", an adaptation of "The best laid schemes of mice and men", a quote from Robert Burns' poem "To a Mouse".
- Spoiler Title: One of the worst of the many examples in Doctor Who, which gives away something that is meant to be a mystery for two full episodes.
- Suspiciously Similar Substitute: Colonel Faraday for The Brigadier.
- Synthetic Plague: The Kraals plan to wipe the human race out with one.
- Table Flip: Done by the Doctor when escaping from Crayford's office.
- Twisted Ankle: Pleasingly subverted when Sarah goes down on her ankle while running away, the Doctor asks if she's alright, and she immediately is.
- Uncanny Valley: Almost certainly invoked with the robot duplicates, but especially the android Doctor, who acts almost exactly like the Doctor, but with just enough subtle malice that makes him profoundly creepy.
- Not to mention the pub scene, wherein the whole pub is filled with androids, just standing there, not moving. Then the clock goes off and they start acting like normal people.
- Presumably the whole point of the replica village was to avert this by "training" the androids on how to at least blend in when they land on Earth.
- Waking Non Sequitur: After being interrogated, the Doctor isn't exactly lucid.Doctor: Once upon a time, there were three sisters, and they lived at the bottom of a treacle well. Their names were Olga, Masha and Iraina. Are you listening, Tilly?
Sarah-Jane: I'm Sarah.
- What Happened to the Mouse?: We never see Benton again after he's knocked out by one of the duplicates. In fact, for many years some fans thought Benton had actually been killed in this story, until Mawdryn Undead revealed that he had retired from the army and become a used car salesman.
- Or Chedaki, for that matter. He doesn't go with Styggron to Earth. What happened to him?
- A second android Sarah Jane is introduced near the end and then immediately forgotten about.
- Whole Plot Reference: The story was inspired by Invasion of the Body Snatchers.
- You Have Outlived Your Usefulness: Pretty much said verbatim by Styggron when he kills Crayford.Styggron: I used you, Crayford, as I used the androids. But you are no longer of any value to me!
- You Said You Would Let Them Go / I Lied