The one with the dinosaur man.
The Doctor and Peri happen upon yet another Crapsack World, under the heel of a mysterious dictator known as the Borad who is trying to provoke interstellar war with some inoffensive handpuppets for apparently no reason. Mirror-fearing robots keep everyone in line, and the preferred method of execution is to be shoved into a one-way portal through time and space. It is called... the Timelash. As the quisling council leader and Large Ham puts it: "Most people depart with a scream."
It seems someone has — whoops! — accidentally fallen into the Timelash (and holding a MacGuffin, what's more), and the baddies want the Doctor to go and get her back. And to make sure he helps, they very originally kidnap Peri. At least, they say they do, but she in the meantime has made contact with a group of rebels in Morlock-infested tunnels, where she does a passable job winning them over with her encyclopaedic knowledge of previous Doctor Who companions. And then a flaming android appears out of nowhere.
Anyway. The other end of the Timelash turns out to be 12th century Scotland, but, due to a collision with the TARDIS, the girl and her MacGuffin have ended up in 1885 instead. The Doctor convinces her to come back, but gets saddled with an overly enthusiastic stowaway in the bargain, named Herbert.
Back on the Crapsack World, the baddies have rounded up the rebels and have started throwing everyone they can into the Timelash, including, of course, the Doctor, once they've got their MacGuffin back. Oh, and Peri is chained up in the caves being menaced by a Morlock (a giant snake monster thing), for reasons that will probably become clear later. The Doctor and others manage to stage a moderately successful coup, even sending a flaming android back in time for good measure. While the new leader of the planet begs the invading sock puppets not to nuke them all, the Doctor wanders off, Herbert in tow, to deal with the Borad.
The Borad turns out to be a weird mutant experimental mixture of two races (who bear more than a passing resemblance to the Morlocks and Eloi of Wells' The Time Machine), and now he wants to kill everyone so that he can re-populate the world with more of his own cross-eyed hybrid kind. And, naturally, he has picked Peri for his queen (can't really disagree with this choice, though). The Doctor defeats him handily with a Power Crystal he picked up from inside the Timelash, frees Peri, and returns just in time to discover that the Sock Puppet Aliens have already fired their missile.
There is nothing for it but to fall back on the old Heroic Sacrifice and interpose the TARDIS between the planet and the missile. Which he does, after forcibly evicting Peri (and being horrified to discover that Herbert has once again stowed away). TARDIS goes boom, and the planet is saved! What's more, the Sock Puppets are suddenly anxious to make peace, realizing that there might be some negative repercussion to just having killed the Lord President of the High Council of the Time Lords.
But what's this? It turns out the Borad is Not Quite Dead (there were clones or something) and still has designs on Peri. Which he proves by threatening to kill her. Fortunately, the Doctor and Herbert are also Not Quite Dead for no adequately explained reason, and the Doctor throws the Borad into the Timelash so that he can spend the rest of his days swimming around Loch Ness and kickstarting the field of cryptozoology.
- Ac CENT Upon The Wrong Syl LA Ble: The Androids talk in a very sing song manner.
- Adam and Eve Plot: The villain's plan is essentially to cause this trope with his own planet and he wants Peri to be his Eve.
- Aliens Speaking English: Conveniently for Herbert, Vena is perfectly comprehensible when she appears.
- Ascetic Aesthetic: The Karfelon citadel is mostly bland and white.
- Beethoven Was an Alien Spy: H. G. Wells was inspired by an adventure with the Doctor.
- Big Bad: The Borad.
- The Caligula:
- The Borad.
- Eric Saward described Tekker as "a Roman Emperor who sniffed glue all day".
- Chair Reveal
- Chekhov's Gun: Peri inspects some plants, gets told they can spread an acidic venom, and then two scenes later? Uses it as a weapon.
- Continuity Nod:
- When the Doctor tells Peri that the Kontron tunnel is a "time corridor in space", she asks, "Didn't the Daleks have one of those?"
- An image of the Third Doctor shows up, as a decoy to lure away androids. One of the rebels shows Peri an image of Jo Grant in her locket in order to verify that she's with the Doctor.
- Cool Chair: The Borad's throne is another in the Great Chairs of Doctor Who line. It moves and has its time-acceleration ray!
- Crapsack World
- Death Wail: The Borad lets out a nice one when he first dies.
- Decoy Leader: The Borad uses the face of an old man to cover for his true identity.
- Even Evil Has Standards: When he learns the Borad's true genocidal plan, even Tekker rebels against him. Unfortunately for him, he chooses to announce this while standing right in front of the Borad's time-accelerating death ray. You can probably guess what happens next.
- Expy: Paul Darrow played Tekker as a caricature of Richard III. Supposedly he was told to stop, but Darrow already knew this episode would be bad and decided to have some fun with the role.
- Fate Worse than Death Apparently being sent to Scotland is this. Was this episode written by Garth Marenghi?
- Ham-to-Ham Combat: Paul Darrow and Colin Baker. Baker had hammed it up spectacularly as a guest star in a Blake's 7 episode, and Paul Darrow apparently decided to get his own back.
- Hand Puppet: Used to represent an alien ambassador. It says something about "Timelash" that this isn't the most ludicrously cheap special effect in the story.
- Hand Wave: How did the Doctor survive the Bandril missile near the end? When Peri attempts to ask this pertinent question, the Doctor brushes it aside and he never does get around to explaining.note
- Heroic Sacrifice: The Doctor, and Herbert steer the TARDIS in the way of a planetary destroying missile.
- Historical-Domain Character: H. G. Wells.
- Historical Injoke
- Historical Person Punchline: The stowaway's full name is not revealed until the final scene (though given the number of shout-outs to his work, it's not hard to guess who he's meant to be).
- Jerkass Façade: The Doctor brusquely orders Peri out of the TARDIS in a way that goes only slightly beyond his usual obnoxiousness... but only so he can pull a Heroic Sacrifice by flying the Tardis into the missile. It strongly calls to mind all the times he's tricked the companions to get them to safety against their will. ("The Parting of the Ways" etc.)
- Large Ham: Paul Darrow. Dear God, Paul Darrow.
- Mars Needs Women: And the Borad needs Peri.
- The Needs of the Many: Herbert muses over two lives being not as important as millions.
- Noodle Incident: The serial is a sequel to an unbroadcast adventure the Third Doctor and Jo Grant had on the same planet.
- Not Quite Dead: After seemingly being aged to death by his reflected time-acceleration ray, the Borad suddenly appears to menace Peri again near the end of the story. Upon being confronted by the Doctor, the Borad's explanation is literally "I must have forgotten to mention I made a clone of myself."
- Out-Gambitted: The Doctor outwits the Borad.
- Rage Against the Reflection: "No! Smash the mirror!"
- Rapid Aging: What the Borad's chair weapon does.
- Sequel Episode: To an untelevised story featuring the Third Doctor and Jo.
- Shadow Dictator: No one has seen the true face of the Borad, only his decoy.
- To several H. G. Wells novels, reasonably enough. Also, the Doctor's line "To be frank, Herbert..." was a nod to Frank Herbert, author of Dune.
- Also, one of the androids replies to a question in the unmistakable five notes that the aliens in Close Encounters of the Third Kind would often repeat. What made it stand out was the fact that usually, the androids would talk in very few, non-musical sounding notes, as opposed to the colorful sound that it did in that one instance.
- Slouch of Villainy: But it's not like the Borad has any reason to stand up.
- Stock Ness Monster: Doesn't appear in the story, but the Doctor speculates that the Borad will inspire the legend of the Loch Ness Monster after he's stranded in 19th-century Scotland.
- Title Drop: The Timelash is the preferred way of execution.
- Vitriolic Best Buds: Peri's reaction when she thinks the Doctor perished in his attempt to stop the missile—and when he turns up alive—shows that despite their bickering, she's very distressed by the prospect of anything happening to him.
- Was Once a Man: The Borad, until a science experiment went wrong.
- You Have Failed Me
- Young Future Famous People: Herbert turns out to be H. G. Wells.
- Your Princess Is in Another Castle!: The Doctor manages to kill the Borad with about 10 minutes to go. Then the Bandrils decide to attack Karfel anyway. Then it turns out the Borad who was killed was a clone...