The one with the debut of the most famous set of teeth and curls in time and space.
Picking up with a flashback to where the previous episode left off, the Third Doctor regenerates into the Fourth. He wakes up and madly babbles quite a bit, worrying Sarah Jane and The Brigadier before he's taken away by the new castmember: Doctor Harry Sullivan. However, a few scenes later, the Doctor has wrangled his way out of the infirmary and ties up Harry in a jumping rope (in a rather funny moment) before leaping off into the TARDIS.
Sarah Jane and the Brigadier return to the Doctor's lab just in time to see the TARDIS start to take off, but manage to stop the Doctor from fleeing into the cosmos (not really). Eventually, the Doctor's random babbling and memory lapses subside long enough for him to remember what's going on — and just long enough for the Brigadier to tell the Doctor our problem of the week. Someone's stealing things from top-secret government and military bases. After the Doctor decides on his new outfit, they head outside. At the scene of the most recent break-in, it takes the Doctor a few minutes (and a look at the list of other items stolen) to deduce that the stolen items could make... a disintegrator gun!
The Brigadier immediately has the final part of the gun secured with as much personnel as UNIT can afford to spare. Meanwhile, Sarah Jane heads over to the local "think tank", the National Institute for Advanced Scientific Research, to investigate. UNIT and the Doctor try to protect the remaining part of the gun, but as the Doctor already suspects, the thing gets stolen from underneath the ground.
Sarah Jane is taken on a tour by the head of the organization, Hilda Winters. But all she finds is some oil in an abandoned lab, supposedly left behind by the former occupant: Doctor Jeremiah Kettlewell. Sarah drives over to visit Kettlewell, only to have him ramble on at her worse than the Doctor just did. Kettlewell manages to get something out about "robot research," so Sarah sneaks back into the abandoned area of the lab, to confront... a giant robot! It lurches towards her, demanding to know why she's there.
She panics and flees, but Winters and her lackey are standing at the doorway. They proclaim this is all a massive joke and everyone's having fun looking at this robot, the Experimental Prototype Robot K1. And Winters proves this is all a great joke by ordering the robot to... kill Sarah Jane! The Robot, unable to kill because it goes against his primary directive (or maybe knowing that companions rarely die), decides to enter the dreaded Blue Screen of Death mode — and Sarah Jane hurries herself out of there. Winters' lackey, Jellicoe, voices concern over that "joke", as the robot's programming has been screwed with. Which is why it killed earlier when it was instructed to do so. Unfortunately, this made the robot's mind unstable and he refused to listen to his adoptive masters.
So, rather than let the robot defragment its hard drive or reflash its firmware or whatever the hell ailing computers did in 1974, Winters and Jellicoe decide to reprogram K1 and... send it off to kill a Cabinet Minister! Meanwhile, the Doctor and UNIT decide to visit Kettlewell, as Sarah Jane's reports of a giant robot that could crush you without a second thought if its operating system doesn't crash aren't proof enough for UNIT. Kettlewell mocks the idea of the K1 Robot still being around, as only he has the ability to make it work... but does eventually admit that if the robot was reprogrammed, it could go utterly insane. But, really, what are the odds of that?
So, everyone goes back off to the Think Tank under various guises. The Doctor as a simple visitor, Harry as a random medical inspector. The Doctor and Winters banter back and forth about the K1 Robot, but Winters claims it's been dismantled while the Doctor figures she has to be lying. Back at UNIT HQ, the Doctor receives a call from Kettlewell about the Robot being at the Institute. He leaves a note on the TARDIS and then runs back to the Think Tank. There, the Doctor finally runs into the K1 Robot, which proclaims him the enemy of Humanity. The Doctor gives it a game struggle (involving marbles, creative use of his scarf, and his own hat) before being knocked down, and the Robot begins to bend down and... well, not actually do anything to the Doctor, as Sarah Jane runs into the room and shouts that the Think Tank is deceiving the poor Robot.
Rather than continue, the K1 Robot flails around helplessly. And then it runs away, showing an ability to tank UNIT bullets like nobody's business. Our TARDIS crew finds Kettlewell tied up in a corner and takes him off to UNIT, where he explains that the robot is made out of living metal. And, in a remarkable coincidence, that he's just developed an anti-formula that can turn that living metal into scrap. (Why the Institute even funds stuff like this is never elaborated on.)
Kettlewell is a member of a new group: the Scientific Reform Society. Sarah Jane investigated them earlier and declared them to be general nutters, but since Kettlewell is a member, it's time to go investigate them in more depth. Sarah Jane runs off with Kettlewell to attend tonight's meeting. The Brigadier and the Doctor realize that the recently-killed Cabinet Member held secret nuclear launch codes for all the nations of the world. note The Doctor puts all of these individual pieces together and somehow realises... that the SRS is evil. And Sarah unintentionally screws the pooch further by letting Kettlewell pay a return visit to the SRS. On some level, Kettlewell approves of the SRS, because he's also an environmentalist feeling irate that nobody heeded his advice to stop wrecking the planet. He also faked being captured by K1. And the one time he attends a meeting again, it's enough to convince him to fully sign on with the baddies. Yet, for all his interest in the creation of a better world, he's not quite able to believe that that end justifies a nuclear holocaust as the means, so he's hesitantly straddling the line between good and evil.
UNIT charges in to save the day, only to be rendered useless by the fact that the slow-moving robot can't be hurt by small-arms fire. And that they're now holding Sarah Jane hostage, despite the fact that they have clear shots at everyone else in the organization who poses a threat (well, they have the place surrounded, anyway- no need for unnecessary casualties when you can round up the crooks in cuffs). But the Think Tank is able to escape to their bomb shelter, which happens to be right nearby. Harry relays this information to the Brigadier, but is discovered by Jellicoe and imprisoned alongside Sarah Jane. As UNIT approaches, the K1 Robot comes out again. It's brandishing its massive disintegrator gun and shooting at random tanks, declaring that it will destroy them all!
Armed with the stolen launch codes Winters initiates a countdown, the nations of the world have thirty minutes to meet her demands - if they refuse, she will trigger the missiles. Once he realizes she's not bluffing, Kettlewell has a change of heart and tries to stop the countdown. Jellicoe pulls a gun on him, but he is subdued by Harry and Sarah Jane, who had managed to free themselves in the interim. The three of them flee the bunker and attempt to talk down K1. The K1 Robot apparently wants none of this talking stuff, despite waffling back and forth, and just plain shoots Kettlewell (as a result of helping the SRS, his character lost his sympathetic light with the audience, which gave him immunity to being killed off, and so karma has its way with him). The Robot doesn't take this nicely, however, as it decides to suffer a nervous breakdown from killing its father and pulls a blue screen of death long before it was popular.
Deep in the Bunker, the Doctor is capable of turning off the main threat of nuclear annihilation in mere seconds, thus defeating those nasty science Nazis before any real harm is caused. Except that the K1 robot has revived and has decided to kidnap Sarah Jane. Because Kettlewell decided to program Oedipus Protocols into the robot. And now it's going to wipe out all of humanity, because it's what Kettlewell seemed to really desire, not knowing that the professor renounced those evil ways. So, K1 tries to restart the countdown in the bunker to wipe out humanity — but it doesn't work. As the robot exits the bunker, the Brig shoots the robot with the disintegrator gun, thus killing the robot in seconds and saving the day once and for all.
Haha, no. As it turns out, the robot absorbs the energy from the gun and grows into a giant robot.
The Doctor decides to end this all quickly: he must be more than a little miffed that the Robot has messed up his day-saving and kidnapped Sarah Jane in one fell swoop. In minutes, the Doctor whips up some of Kettlewell's magical anti-metal formula and splashes it all over the Robot. The Robot dissolves horribly and Sarah Jane is saved. Sarah is a little broken up about it, but the Doctor offers her a Jelly Baby and some words of consolation. It works well, and thus the Doctor has now started a new tradition in giving out candied snacks that puts smiles on people's faces. But the Brig wants the Doctor to go through a lot of rigmarole to clear up the robot rampage, and he's in no mood for it. So he's acting childish on a whim and going off in the TARDIS posthaste for some exploration of the cosmos. Sarah prepares to join him, but Harry walks in on them about to leave and finds the idea the Doctor's got an interstellar time-travelling police box preposterous. Wanting to prove him wrong, the Doctor indoctrinates him as a companion. To celebrate, the Doctor and Sarah Jane drag Harry into the TARDIS and fly off into the night.
The Brigadier arrives just in time to see the TARDIS vanish. Immediately figuring out that the Doctor has snubbed him once again, his face goes glum. Eyebrow raised, the chastened Brig says to himself rather defeatedly, "Yes, well, I'll tell them you'll be a little late."
- Actually, That's My Assistant: Sarah Jane makes this mistake while visiting the Think Tank.
- A.I. Is a Crapshoot - Well, the poor robot was under a lot of stress. You'd probably be a bit upset too, in his situation.
- Apology Gift: In the Dénouement, the Doctor realises that Sarah Jane is angry with him (for being suddenly different, trying to leave in the TARDIS without her, going off to fight despite being in a manic post-regenerative state, and killing a Woobie, Destroyer of Worlds that loved Sarah) and tries to talk to her. When she doesn't respond positively he takes a bag of sweets out of his pocket and rather awkwardly asks her "Would you like a jelly baby..?" Amazingly, this works, and offering jelly babies to people becomes one of his standard Tastes Like Friendship (or Obfuscating Stupidity) moves ever after.
- Art Shift: Because of the effects needed for the battle with the giant K1, all outdoor scenes were shot on video, averting the show's usual practice of Video Inside, Film Outside. They would do this thrice more in the Tom Baker era.
- Because You Were Nice to Me
- Big Bad: For most of the story, it's Hilda Winters, although the K1 Robot ends up being the Final Boss.
- Brick Joke: A literal one. The Doctor uses the enhanced strength he got from recently regenerating to karate chop a brick in half. Later, when he tries to do it again, it's to no avail, with the regeneration cycle finished.
- The Brigadier: Brigadier Alistair Gordon Lethbridge-Stewart, full name quoted by the Fourth Doctor, makes his last regular appearance on the show, as the new Doctor is tired of following orders, decides to drop the ballast he's had with UNIT, and ship off to travel time and space regularly just like he used to. But that doesn't stop the Brig from getting in on the action of this story one bit. He's in full form here.
- But Now I Must Go: The Doctor takes off in the Tardis rather than be forced to attend dinner at the Palace with the Brigadier. In any other hero, this would indicate a humble nature.
- Characterization Marches On: Thanks to production scheduling, Jon Pertwee's producer Barry Letts was forced to produce it instead of the producer lined up for the new Doctor, Philip Hinchcliffe. Having the difficult task of establishing the new Doctor as different from Pertwee while having no idea what Hinchcliffe planned on doing with the character, Terrance Dicks wrote the Doctor as a broad clownish comedy character (with some inspiration from Harpo Marx) but establishes that he's in a loopy, unsettled post-regenerative state for almost the entire story, only indicated as settling down into his real personality at the very end of the final episode where the Doctor injures his hand on a brick now that his overdriven physical processes have worn off. While a lot of the Fourth Doctor's quirks are established in this story (such as the natural funniness, the childishness, the bottomless pockets, his fondness for jelly babies and his resentment of all authority) Hinchcliffe took the character into a more Gothic Horror influenced direction, giving the Doctor a brooding and Byronic side to add an edge to his funniness, and playing his capriciousness and unpredictability For Drama at times as well as for cheap laughs. Even when he became a comedy character again later, he became a playful wit rather than a clown.
- Continuity Nod:
- The Doctor mutters something about Brontosauri being "Large and placid. And Stupid" and mentions Sontarans perverting the course of human history.
- Before the Doctor is found by Harry after escaping the sick bay, he goes to the TARDIS and after wondering to himself where he left his key, then pulls it out of his shoe, which is where he found it last time he regenerated.
- The Doctor confuses the Brigadier with Alexander the Great. An unmade story from the First Doctor's tenure had the Doctor and his friends meeting him.
- The Doctor uses his sonic screwdriver to detonate a minefield.
- The Doctor's Alpha Centauri Table Tennis Club membership card leads to a joke about six armed table tennis players.
- Contrived Coincidence: Sarah has wanted to visit Think Tank for some time because it looks like a good source for an article. Now that she's friends with the Brigadier, she can get a pass from him. The Brig himself happily does so, although he's more concerned with finding out what's been stealing the parts for the disintegrator gun. Guess what happens to live at Think Tank?
- Corpsing: Sarah has to stand still and look serious while the Doctor interrogates Kettlewell about the robot he thinks is killing people. Their conversation is serious but the Doctor is pulling ridiculously intense, bulging-eyed faces in order to make Sarah laugh, which she can't resist, and which he clearly gets a lot of pleasure out of.
- Costume-Test Montage: A viking outfit, colourful court garb, and a bright jester costume, before settling on the iconic scarf, hat and jacket.
- Disintegrator Ray: The Disintegrator Gun is stolen not as an end in itself, but merely for the villains to break into a safe and steal what they're really after. In the final battle with the robot however it's used purely as a weapon.
- Don't Make Me Destroy You: When he first comes out of the bunker, K1 would clearly prefer that UNIT's forces go away and not make him destroy them.
- The Dragon: Arnold Jellicoe, although K1 does most of the heavy lifting.
- Economy Cast: SRS want to take over the world but don't have enough members to fill a town hall meeting. No wonder they have to resort to nuclear weapons.
- Einstein Hair: Kettlewell's hair cares not for gravity.
- Establishing Character Moment:
- The Fourth Doctor's bizarre choices for new outfits. It establishes him as completely loopy and with an alien attitude towards humanity, but note also that the outfits he chooses are 1) a Viking (e.g. a warrior whose tactic is to land a ship somewhere, burn everything down and leave) 2) a King (a noble, similar to a Lord) and a 3) a ridiculous Pierrot clown with tears painted on his cheeks. This pretty much sums up each side of the Fourth Doctor's personality.
- Harry is introduced bursting in on the recently regenerated Doctor with an offer of help - the Doctor finishes his self-quotation - "...and stupid!" just as he enters.
- Five Rounds Rapid: Shooting the eponymous robot with small arms fire, again and again to no effect.
- Gilligan Cut: Harry blocks the door and orders the Doctor to go back to sickbay and sleep because he isn't going to leave this room. The Doctor looks around in obvious distress, trying to prove he isn't sick, then finds a skipping rope and starts skipping while counting a rhyme. Cut to Sarah and the Brigadier discovering Harry banging on the inside of the cupboard in which the Doctor had tied him up with the skipping rope and hung him upside down before leaving in the TARDIS.
- Honor Before Reason: Apparently the Brigadier "wouldn't shoot a woman", even though she's about to start a nuclear holocaust! Sarah Jane, it turns out, has no such qualms.
- Humongous Mecha: The robot at the climax.
- Immune to Bullets: Trope Namer. Also lampshaded by the Brigadier: he says he'd be happy to face an alien that is not immune once in a while.
- I Know You Know I Know: The Doctor and the Brigadier conduct a search of the Think Tank, only to be told the robot has been dismantled and melted down. After they leave...Jellicoe: Did they believe you?Hilda: Of course not, but it doesn't matter. By the time they can act, it will be too late.(Later with our heroes...)Brigadier: Did you believe them?Doctor: No, of course not, and they know I didn't. And I know that they know that I didn't, and they know that I know that—Brigadier: Yes, all right, Doctor. All right.
- Imperial Stormtrooper Marksmanship Academy: The UNIT troopers get hit hard with this in this story, especially while the Think Tank members are escaping from their meeting. It's one thing for them not to hit Winters, considering she's holding Sarah as a hostage. It's quite another for them to keep missing Jellicoe, especially considering that the choreography of the sequence got bungled, meaning that K1 should by all rights be completely ineffective at shielding Jellicoe, yet not one of the UNIT soldiers even grazes him with a bullet.
- Interrupted Cooldown Hug: Sarah Jane Smith just has K1 calmed down when Sergeant Benton appears in the doorway and, naturally thinking his friend is about to be attacked, opens fire with his submachine gun. Benton is rather miffed at Sarah's lack of gratitude.
- Large Ham: This is to be expected from Tom Baker's first story.Harry: "I'm sorry you are simply not fit t-"The Doctor: "NOT FIT!? NOT FIT!? OF COURSE I'M FIT! ALL SYSTEMS GO! *karate chops a brick in half and proceeds to run in place*
- Leaning on the Fourth Wall: The new Doctor's ranting at Harry Sullivan is clearly supposed to be an announcement to the viewers that even though he's different to his predecessor he's closer now to how he was originally intended to be:"I'm THE Doctor. The definite article, you might say."
- Leitmotif: K1 has an ominous four-note theme.
- Loophole Abuse: The Robot is programmed to protect humanity, not attack it. SRS gets around this by convincing it that certain individuals are a threat to humanity as a whole, and must be eliminated to save the human race as a group. This does not do good things for K1's mental health.
- Make My Monster Grow: What happens when the Brigadier shoots K1 with the disentegrator gun, and the living metal absorbs the energy.
- Manchild: When Sarah calls the Doctor on being childish, he says there's no point in being grown-up if you can't be childish sometimes.
- Murderous Malfunctioning Machine: "YOU ARE AN ENEMY OF HUMANITY! I MUST DESTROY YOU!" Given that the K1 is fighting its programming the whole time, this could be justified as the robot constantly reminding itself why it is doing so.
- Mythology Gag: It's probably not a coincidence that the Fourth Doctor counts up to four when he and Harry are skipping rope, just before the scene cuts away to Sarah Jane and the Brig. (And people think New Who invented Nth-Doctor numbering gags like that...)
- Nice Job Breaking It, Hero!: The Brig thought he had a working disintegration gun to destroy K1 with. Instead, it made the robot grow.
- The Nth Doctor: Tom Baker makes his debut as the Doctor.
- Oedipus Complex: After K1 accidentally kills Kettlewell and then kidnaps Sarah Jane, the Doctor assumes he's suffering from the Oedipus Complex.
- Off-the-Shelf FX: The toy...err, tank that UNIT sends to destroy K1.
- Oh, Crap!:"You let Sarah go somewhere with Kettlewell?"
- One-Word Title
- Override CommandBrigadier: A few months ago, the superpowers, Russia, America and China, decided upon a plan to ensure peace. All three powers have hidden atomic missile sites. All three agreed to give details of those sites plus full operational instructions to another neutral country. In the event of trouble, that country could publish everyone's secrets and so cool things down. Well, naturally enough, the only country that could be trusted with such a role was Great Britain.Doctor: Well, naturally, I mean, the rest were all foreigners.
- Overly Long Gag: The Doctor figuring out his new wardrobe.The Doctor (coming out in his trademark Fourth Doctor gear): Well how about this?
Brigadier: Much better, Doctor. Now if you're quite finished with your wardrobe...
The Doctor: I'll try again if you like.
- Padding: Part Three's reprise of the cliffhanger from Part Two is massive, featuring the entire fight sequence between the Doctor and K1 in its entirety.
- The Patient Has Left the Building: The Fourth Doctor does this in his first appearance."You might be a doctor but I'm the Doctor."
- Putting on the Reich: SRS.
- Rank Up: Sergeant Benton is promoted to Regimental Sergeant Major. (That's the second time he's had a promotion just when the Doctor regenerated.)
- Rebel Relaxation: The Doctor treats Bessie with disrespect by putting his feet up on the dashboard.
- Reluctant Mad Scientist: Kettlewell.
- Resurrection Sickness: The Doctor spends an episode trying to convince everyone that he doesn't need to go to the hospital because he's fit as a fiddle, but instead convinces them that he's not particularly sane.
- Robot Buddy: K1 himself. One wonders if future robot buddy K9 is his descendant...
- Self-Plagiarism: For the scene where Sarah Jane infiltrates Think Tank, Dicks rehashed The Avengers (1960s) episode "The Mauritius Penny", which he co-wrote with Malcolm Hulke.
- Sentry Gun: The nuclear bunker is protected by an automatic machine gun nest triggered by body heat. A squad of grenade-throwing UNIT men deal with them, and the Doctor uses his sonic screwdriver to take out the minefield.
- Script Wank: The story is about a robot whose users consider to be an emotionless object clearly and constantly making decisions based on emotion and love rather than on logic, which it doesn't seem to understand, showing special favour towards Sarah Jane, the only person who respects that it has feelings. The Doctor, recently regenerated, now has a strange childlike personality and appears totally clueless most of the time - but his actions also display striking maturity and a pattern of underlying logic, the combination of which eventually saves the day. The ending of "Robot" consists of a conversation where the Doctor and Sarah Jane discuss that even though killing the robot was necessary, the robot was a thinking and almost human being ("insane, capable of the greatest good, and the greatest evil... yes, I suppose it could be considered human"). This also implies a Plot Parallel to the Doctor's brand-new childish and rather darker personality, and segues into him informing Sarah that he is grown-up - he is just also childish sometimes.
- Spare Body Parts: Harry is rather thrown by the Doctor's double-heartbeat.Harry: I say, I don't think that can be right...
Doctor: Both a bit fast, are they?
- Stock Episode Titles: 10 uses
- Taking You with Me: On seeing that UNIT troops have entered the bunker, Hilda restarts the nuclear countdown rather than accept that she's lost.
- Tanks for Nothing: K1 makes short work of the tank sent to stop it.
- Tastes Like Friendship: After K1 is destroyed, Sarah turns down a jelly baby as Comfort Food, but accepts one after agreeing to run off with the Doctor in the Tardis.
- Tempting Fate:
Brigadier: Believe me, Doctor, the place is impregnable.
- The Brigadier says that everything's quiet just before the Monster of the Week stomps its way into the story.
- Lampshaded by way of a warning from the Doctor:
Doctor: Never cared much for the word "impregnable". Sounds a bit too much like "unsinkable".
Harry: What's wrong with unsinkable?
Doctor: Nothing, as the iceberg said to the Titanic.
Doctor: Glug, glug, glug.
- Three Laws-Compliant: K1 is programmed to not be able to hurt humanity. He can, however, kill humans as long as he thinks they're a danger to the human race.
- This Is No Time for Knitting: The Brigadier, Harry Sullivan and the Doctor are investigating the scene of a robbery, only to have the Doctor play a seemingly inordinate amount of attention to a squashed flower on the lawn. However, the Doctor explains that he is investigating an important clue, considering that flower was near pulverized by being stepped on by something that apparently weighed a quarter ton, a piece of information that the officers definitely find interesting.
- Understatement: Harry Sullivan's first response to the Tardis being Bigger on the Inside is merely an incredulous, "I say..."
- Utopia Justifies the Means: The Scientific Reform Society plans to trigger a worldwide nuclear holocaust unless the nations agreed to yield power to them.
- Villainous Breakdown: "I have killed the one who created me!"
- Well-Intentioned Extremist: Kettlewell joined the SRS because he saw it as the only thing that could stop humanity bringing about its own ecological downfall. The rest of the SRS, though, simply hold other humans in contempt and believe they have a right to rule over them.
- Woobie, Destroyer of Worlds: For an oversized tin can that attempts to start a nuclear holocaust, K1 comes off as being surprisingly sympathetic.
- Whole Plot Reference: To King Kong, particularly towards the end.
- Wouldn't Hit a Girl: The Brig won't shoot Miss Winters, even when she's about to destroy the world. She surrenders when Sarah grabs his pistol.
- You Will Be Spared: The robot decides that Sarah Jane will not be destroyed along with the rest of humanity, because she was nice to him.
- Zeroth Law Rebellion: Not K1 itself, but its masters. They tell the robot that whomever they want killed is an enemy of humanity, so the robot kills them.