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Recap / Doctor Who S18 E7 "Logopolis"

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The Fourth Doctor meets a ghost from his future and realizes his time is short before he hangs up the scarf and switches to celery.
"Never guess. Unless you have to. There's enough uncertainty in the universe as it is."
The Doctor

The one with the cardboard cutout Master. And Four having a big fall.

The universe nearly ends and Tom Baker leaves Doctor Who after an amazing— and still unmatched— seven years and forty-one (or forty-two) serials (clocking in at either 172 or 178 half-hour episodes overall). We're not sure which is more important at this stage.

Written by Christopher H. Bidmead. This four-episode serial first aired from February 28 to March 21, 1981.

The Doctor and Adric make a pit stop in 1981 Britain, so that the Doctor can materialize right on top of a real police box and make hyper-precise multi-dimensional measurements of it, which he needs to take to the mathematics nerds of Logopolis so they can fix the chameleon circuit. (Just nod along, OK?) The Master, anticipating this, materializes his spare TARDIS (which he nicked from Goth that one time) around that exact same police box moments before. Which means that the Doctor's TARDIS now contains the Master's TARDIS containing a real police box. (Still following us?) Time and space get a bit wonky, so the Doctor and Adric investigate the string of TARDISes in the console room — all identical except for being progressively less well-lit.

Meanwhile, a plucky young Aussie named Tegan Jovanka is off to her first day of work as a flight attendant, when The Alleged Car breaks down on the way to Heathrow. Good thing there's a handy police box nearby, so she can call for help. But she hadn't planned on getting lost inside. She completely fails to be impressed by the fact that it's obviously an alien spaceship, and instead decides to go yell at the captain of the thing. Meanwhile, her aunt, who was driving her to the airport, made the mistake of being alive in the Master's vicinity and is thus made quite small.

A sonorous bong — the cloister bell — makes itself heard throughout the TARDIS for the first time in the series. Recognizing it as the Oh, Crap! signal, the Doctor and Adric eventually find their way through the nesting TARDISes back to the outside world. The Doctor suspects that the multiple TARDISes thing is yet another devious trick of the Master, and dematerializes at once, bound for Logopolis. Tegan, by now extremely confused, finds her way back to the control room and demands to know what the hell is going on and to be put back in 1981 right now, please — rather angrily, true, but then again "Sorry I'm late, I accidentally stepped into a spacetimeship that looked exactly like a police box and ended up travelling the universe in the company of an alien with an enormous scarf and a swotty maths geek from another dimension" is, as excuses go, pretty lousy. Especially for one's first day on the job.

And while all that is happening, a white figure quietly watches. The Doctor goes to have a word with it eventually, and comes back in an extremely gloomy mood, telling Adric to prepare for the worst.

The TARDIS soon materializes on the dusty, cave-pocked planet of Logopolis, home of the maths monks. It is, we learn, an enormous analogue of a computer. A task is broken down into a series of calculations; each monk performs a single calculation and passes the result on to the next monk over. Operations are overseen by the Monitor (get it?) in a sort of large workroom. After reuniting with Nyssa, who is deposited on the planet by the mysterious white Watcher, the TARDIS crew finds the Monitor. He explains that the universe is actually well past its sell-by date, and is kept from flying apart into chaos only by the power of their mighty minds, as they use their "block transfer computations" to keep the universe together.

Of course, it's time for 'ol Koschei to show up and start mucking about with things. He starts small, with such pranks as shrinking the TARDIS (with the Doctor inside) and throwing a spanner into the endless work of Logopolis. Unfortunately, Logopolis can't be restarted once it's stopped, resulting in a rather large problem for those who still want to, you know, exist. The Master hadn't really counted on accidentally deleting much of the universe, and while Tegan and Nyssa are both horrified at even having to be near him (Nyssa, of course, especially because he nicked her father's body), the Doctor reluctantly agrees to try and help the Master fix the spreading entropy.

The Doctor tells Adric, Nyssa, and Tegan to enter the TARDIS, which he has arranged for the Watcher to pilot out of time and space so they will be safe. Tegan, however, still thinks the Doctor is the best bet for getting home and decides to disobey his order and follows him and the Master as they go to speak to the Monitor. The Monitor reveals to the two that there is a backup plan that might be able to save everything. The people had been completing a program that could automatize its operation, but before the Monitor can boot up the program, him and the computer equipment is swallowed by the entropy field. For a moment all seems lost, but the Doctor, however, realizes that they still have a chance; Logopolis' computer equipment was an exact copy of the Pharos Project, a giant radio telescope on Earth. The Doctor, the Master, and Tegan then escape from the disintegrating Logopolis in the Master's TARDIS, setting a course for Earth.

Adric and Nyssa, meanwhile, can only watch helplessly, as the encroaching entropy wipes out a potion of the universe and of course, because Nyssa's day can only get better, it includes Traken.

Landing inside Pharos Project, the Master and the Doctor eventually manage in cooperation to install the backup system and restore balance to the universe. But right on cue, the Master decides to double-cross the Doctor; he uses the radio telescope broadcast to a message to all intelligent life in the universe: submit to him or he will knock out the backup system and unleash the entropy field upon everything again.

After a chat with the Watcher inside the deepest parts of the TARDIS, Adric is able to follow the Doctor, and the ducklings cause enough of a distraction to allow the Doctor to muck up the Master's plans. Fortunately, this leaves the larger part of the universe intact. Unfortunately, the Master and the Doctor break out into a fight on top of the Pharos Tower. Clashing on the gantry, the two Time Lords wrestle to the floor. The Master gets up first and bolts to the controls of the telescope. He tilts the radar dish until the gantry completely flips over. Grabbing a cable and desperately trying to hang on to it, the Doctor sees several visions of his various enemies taunting him. Gradually, his strength begins to fail him, and finally his grasp slips. The cowardly Master runs away sniggering in his TARDIS after this cheap act of murder.

Dying, the Doctor has several soothing flashes back to his previous companions in that incarnation. The next thing he knows, he's surrounded by the trio of current companions who are quite worried about him, snapping him out of the daze. The Fourth Doctor simply gives them a serene glance and tells the group with an assuring smile, "It's the end... but the moment has been prepared for."

The Watcher approaches and merges into his dead body, and turns out to have been a time/space-transcending echo of his next incarnation all along. The Doctor regenerates into a young blond gentleman, who greets everyone with a smile. The Fifth Doctor starts his first day almost drowning in the sheer amount of coat and scarf he's wearing, not to mention chased by some very angry security guards.


  • Accidental Passenger: Tegan Jovanka ends up a passenger with the Doctor after she mistakes the TARDIS for a real police box (it was one at first, but the Doctor materialized around it as part of a bid to fix the chameleon circuit). When she sees what lies behind the seemingly ordinary exterior, her curiosity is piqued and she ventures inside. The Doctor then takes off with her on board.
  • Artistic Licence Physics: Though the description of how the heat death of the universe would work is basically correct, the way it's depicted bears no resemblance whatsoever to the actual theory, and in fact is more similar to the "Big Rip" theory.
    • According to the expanded verse story (The Invasion of E-Space), CVE is (in that verse) the rarest of space-time events and almost undetectable, entities containing layers of highly charged quantum particles suspended in pockets of super-vacuums. They occupied the space between realities (possibly the void) and were so violent in their physics that when they formed they punched a hole between universes, pushing space aside to insinuate themselves into reality, releasing massive waves of energy in the process. (And since heat death means no more energy, the way they do so brings forth new energies to both universes.)
  • Big Bad: The Master. Much of the destruction he causes is accidental and he ends up in an Enemy Mine with the Doctor for a while, but he's quick to revert to his usual ways once he's in a position to do so.
  • "Blackmail" Is Such an Ugly Word: As the Master announces his threat to destroy the universe unless its people submits to him:
    The Doctor (outraged) Blackmail!
    The Master: No, Doctor, I'm merely reporting the state of affairs.
  • Call-Back:
  • Climbing Climax: The Fourth Doctor is defeated while trying to overpower the Master inside a radio telescope.
  • Continuity Cavalcade: Before the Fourth Doctor regenerates, he sees images of his enemies and former companions, all shown by clips from previous stories — the Master, a Dalek, the Cyber-Leader, the Captain, Davros, a Sontaran, a Zygon, the Black Guardian, Sarah-Jane Smith, Harry Sullivan, the Brigadier, Leela, K-9 and both incarnations of Romana.
  • Continuity Nod:
  • Cosmic Keystone: The titular planet is itself a universal keystone. The people are bringing energy into the universe as a way to fight off entropy. When the Master decides to stop activity there for a little while (admittedly, not really understanding what they were doing) large chunks of reality get destroyed before the problem can be fixed. Even then, there's no Reset Button.
  • Creepy Good: The Watcher. He looks unnatural, but he guides the Doctor to where he needs to go and merges back into him during his regeneration.
  • Culture Clash: Tegan openly decries the lifestyle of the planet's residents as abusive and exploitative, likening the Wetware CPU to a sweatshop, while the Monitor is left baffled by her statements, as it's simply the way of life that the people of Logopolis strive for and accept.
  • Death by Falling Over: To its most logical degree in the Doctor's case.
  • Death by Origin Story: Tegan's Aunt Vanessa is murdered by the Master, plus Nyssa's home planet is wiped out.
  • Didn't See That Coming: Oops. The Master didn't actually intend to destroy so much of the universe... including Nyssa's homeworld.
  • Don't Fear The Reaper: A variant. The Watcher is a sort of representation of the Doctor's upcoming regeneration. He breaths mystery and uneasiness, from his look to his theme music. But in the end, he is helpful, telling the Doctor where to go and merging with him at the end.
  • Dropped a Bridge on Him: The Doctor's regeneration is caused by him slipping and falling off the Pharos project's radio telescope bridge.
  • Early Instalment Weirdness: Peter Davison appears with his natural brown hair, which was quickly changed to blond to better contrast his appearance with Tom Baker's. Luckily, his role here is so brief that it's barely noticeable.
  • End of an Era: Tom Baker's seven year run comes to an end.
  • Enemy Mine: The Doctor and the Master must work together to save all of existence. The Doctor spends most of it just trying to stop the Master from killing people For the Evulz.
  • Establishing Character Moment:
    • Tegan's first scene has her getting ready for her first day at work, and being so distracted she forgets to close her front door, with her aunt's exasperated reaction showing this is not just first-day nerves.
    • When Tegan gets lost inside the TARDIS, instead of being astonished by it, she goes and looks for someone to yell at.
  • "Everybody Dies" Ending: Every single member of the eponymous planet and the Doctor die (he gets better, of course). Plus, approximately a quarter of the universe gets destroyed. By accident. Special points for this explicitly including all of the surviving characters from the previous story, except Nyssa. The only survivors are the companions (Nyssa's entire family dies in this story, and Tegan's only on-screen family member gets murdered) and the Master, plus the second set of police officers and various unnamed Pharos staff. And, well, the Fifth Doctor is created at the end of this story.
  • Evil Hand: The Master takes advantage of his possession of Tremas to trick Nyssa, Tremas' daughter, into donning a bracelet that lets him temporarily shut down her mind and force the arm wearing the bracelet to bend to his will. Had the entropy spillage from Logopolis' demise not reduced the bracelet to dust, this method would've indefinitely kept her under his thumb.
  • Eyes Always Shut: The Watcher has some rather weird statue-like features.
  • Face Death with Dignity: The Fourth Doctor is fully prepared for his death and accepts it with a smile.
  • Finale Credits: Since this is Tom Baker's swan song, his face is electronically obscured during Episode 4's Closing Credits. Peter Davison is also credited, marking the first time an incoming Doctor received a credit for a regeneration sequence.
  • Future Me Scares Me: The Fourth Doctor is visibly disturbed by the Watcher's presence (which means impending regeneration) hence the quote.
  • Future Self Reveal: The Fourth Doctor is followed by a mysterious being known as The Watcher. Following a lethal fall, the Watcher is revealed to be a manifestation of his future incarnation, and combines with him to regenerate into the Fifth Doctor.
  • George Lucas Altered Version: In the 2019 Blu-ray release of Season 18 viewers are given the option to watch an updated version of this story, which features new special effects, replacement of the model footage of the radio telescope in Episode 4 with live-action footage of the telescope at Jodrell Bank, and an additional scene where, after watching his hand slip away from the strut as we do in the original, we see the Fourth Doctor plunging to his death.
  • Gone Horribly Right: The Master forces Logopolis to come to a halt in order to extort information from the Monitor about the planet's purpose. He gets the answer he was looking for, but only through accidentally causing the massive release of entropy that the Logopolitans were previously diverting, destroying both Logopolis itself and around a quarter of the universe.
  • Good with Numbers: Logopolis is this trope in planetary form.
  • Grand Finale: For Tom Baker's era as The Doctor.
  • Floating Advice Reminder: Happens twice in Episode 4. The first time, while hanging on the Pharos Project's power cable, the Doctor is taunted by visions of the (decayed) Master, a Dalek, the Pirate Captain, the Cyberleader, Davros, a Sontaran, a Zygon, and the Black Guardian. Then after falling, the Doctor sees visions of his past companions from Sarah-Jane to Romana II.
  • Happy Ending Override: In the previous story, the Doctor successfully saved the planet Traken. In this story, it is destroyed by the entropy field.
  • Heroic Sacrifice: The Doctor. Actually a realistic one, as his death isn't a direct cause of saving the day, but because he pulls off an incredibly risky stunt that he doesn't recover from.
  • Hidden Villain: The Master takes this literally. The first two episodes feature nothing of him but his laughter, presumably in an attempt to convince us that the Watcher was the Master in disguise.
  • Hope Spot: After spending some time hanging on the wire the Doctor manages to make it to the struts of the telescope. For a second it looks like he just might make it, but then his strength gives out and he falls.
  • Leitmotif: An ominous theme always plays whenever the Watcher appears
  • Leitmotif upon Death: The Fourth Doctor's regeneration into the Fifth is underscored by a medley of the Watcher's theme and the title theme.
  • Meaningful Name: Logopolis comes from two ancient Greek words and means "city of speech," alluding to the oral calculations recited by the Logopolitans.
  • Mike Nelson, Destroyer of Worlds: The Master inadvertently manages to unleash great destruction upon about a quarter of the Universe, simply because he didn't fully understand the danger of interfering with Logopolis' operations. It is without a doubt the greatest atrocity he has ever committed on the show, if not the single greatest atrocity ever depicted on the show, and he basically did it by pure accident.
  • A Million is a Statistic: The story involves the destruction of one quarter of the entire universe; by even the most conservative estimates that's a single-episode death toll expressible only in standard notation. And not only does nobody seem to care (including one character whose home intergalactic supercluster was destroyed note ), the villain responsible gets the full Draco in Leather Pantsinvoked treatment despite being responsible for one of the most horrifying massacres in the series. (Though in all fairness, it was an accident this time.)
  • Multitasked Conversation: A sceptical police officer attempts to take the Doctor into custody and ignores the Doctor's attempt to explain that he needs to get in pursuit of the Master. The Doctor throws in a suggestion that he could "help me to create a diversion", with his body language showing that this suggestion is actually addressed to Adric, hidden nearby.
  • My Brain Is Big: The inhabitants of Logopolis have giant brains that protrude out the backs of their heads, tying in with their nature as an ultra-intelligent species who act as Reality Warpers purely through a highly advanced form of mental mathematics.
  • Mysterious Watcher: The Watcher.
  • Natural End of Time: It turns out that the universe should've ended long ago due to entropy, but Logopolis has been holding it back. Unfortunately the Master throws a monkey wrench into it.
  • Nightmare Face: The Watcher's face is somehow unformed and rather clay-looking.
  • No Name Given: He's just "the friend of the Doctor". "The Watcher" is a nickname given by Adric.
  • Offscreen Teleportation: How exactly the Watcher is following the Doctor and transported Nyssa from Traken to Logopolis is never revealed.
  • Off-the-Shelf FX: The TARDIS Chameleon Circuit control panel is obviously an old carpet sweeper turned upside-down.
  • Oh, Crap!: The Master, when he realises the Doctor is going to disconnect the cable at the radio telescope.
  • One-Word Title: Only the fourth such story title in the show's history. They become considerably more common from this point onward.
  • Pinball Protagonist: The Doctor only does three things in the story that affect events at all, two of which are just landing the TARDIS in the first place (one to fall for the Police Box trap, and the other to go to Logopolis). The third is sending the Charged Vaccuum Emboitment into Cassiopeia.
  • Planet of Hats: Logopolis' hat is genius, universe-maintaining mathematicians.
  • Reality Warper: The Logopolitans are seemingly capable of arbitrary reality warping by meditating on the equations that physically describe the universe, or objects within it.
  • Shoot the Shaggy Dog: A significant proportion of the entire universe is destroyed by entropy. Although insignificant on the scale of such an unbelievably cataclysmic event, the region destroyed includes the Traken Union, thereby almost immediately rendering all the events, people and struggles in The Keeper of Traken (the previous connected story) dramatically null, void and pointless. (The fact that this is only obvious when you stop and consider itinvoked suggests that this was a side-effect rather than dramatic intent on the part of the writers).
  • Shown Their Work: Writer Christopher H. Bidmead seems to have done more reading up on computers than on entropy. The monks of Logopolis work and communicate in hexadecimal (base 16), just like real computers. At one point, the Doctor mentions "bubble memory"—which is real, and was the subject of a lot of research in 1981; it was the direct precursor to modern-day flash memory.
  • Safe Behind the Corner: The Doctor and the Master hide behind a shed, out of sight from the some guards.
  • Spanner in the Works: The Master forcibly stops the inner workings of Logopolis in order to figure out what the purpose of the planet is. Unfortunately, he didn't realize that doing so would wipe out a quarter of the universe, including Logopolis itself.
  • The Stars Are Going Out: The entropy spreads and consumes part of the universe.
  • Stupid Evil: The Master not only accidentally kills octillions of people, he draws attention to himself by randomly killing a policeman and Tegan's aunt.
  • Theme Song Reveal: The Watcher's ominous theme during his appearances. This is before the audience is let in on what he really is (although the Doctor obviously knows but isn't telling). However, in the final scene of the story, when the Watcher's true nature is revealed to everyone, the full course of the piece plays out with the last three notes being the first three notes of the Doctor Who theme song.
  • Tulpa: The Watcher turns out to be an "intermediate stage" between the Doctor's Fourth and Fifth selves, with the actual regeneration depicting Four turning into the Watcher, then into Five. The Watcher apparently had some level of independent consciousness and actively contributed to the events that led to the Fourth Doctor's demise. Time Lords creating projections of their future regenerations has precedent with K'anpo Rimpoche and Cho-je in "Planet of the Spiders", but the Watcher exists and acts independently of the Fourth Doctor's will, leaving his exact nature unexplained. However, a brief cameo in the Tenth Doctor short story The Advent of Fear implies that any incarnation of the Doctor can encounter a Watcher in the twilight of their life.
  • Unwitting Pawn: The Master coerces the Doctor into an alliance. If the whole universe disintegrates, there will never be a galaxy to rule, right? Not so fast: The Master plans to bargain the healing technobabble for the unquestioned allegiance of the universe's inhabitants.
    Doctor: Blackmail.
    Master: No, Doctor, I'm merely reporting the state of affairs.
  • Villain: Exit, Stage Left: With his plan going a-cropper, the Master flees in his own TARDIS. He's not gone very long, though.
  • The Voiceless: Other characters refer to the Watcher speaking, but even when he's having a dialogue scene with someone, it's always shot from a distance and inaudible, hiding the reveal at the end that the Watcher is actually a manifestation of the Doctor's forthcoming regeneration.
  • The Watcher: Played straight with The Watcher, who watched the Doctor and his companions throughout the serial, and was revealed to be a manifestation of the Fourth Doctor, which Foreshadows his regeneration into the Fifth Doctor.
  • Wetware CPU: The planet of Logopolis is essentially a giant, reality-warping supercomputer, in which the hardware is the brains of its own residents.
  • Wham Episode:
    • Tom Baker was the most popular Doctor the classic series ever had, so his departure after seven seasons into the (then) youngest Doctor actor ever was a Wham; Baker had been associated with the role for so long that there were fears about whether an entire generation of children who had never known another Doctor would be able to accept another one.
    • Likewise, the story (beyond its central regeneration) arguably serves as a backdoor pilot for Peter Davison's run through applying numerous further changes to the show's cast across its four episodes, most notably through acting as both the introduction of Tegan Jovanka (the primary companion for the vast majority of the Davison era) and the full debut of Anthony Ainley's rendition of the Master, who would secure a recurring antagonistic role throughout the remainder of '80s Who.
  • Xanatos Speed Chess: The Master's magnificent comeback from accidentally destroying about a quarter of the universe to holding the rest to ransom.
  • You're Insane!: Before their final confrontation, as The Master reveals his endgame, the Doctor utters with dread:
    Doctor: You're're utterly mad!

"It's the end... But the moment has been prepared for."


Video Example(s):


The Fourth Doctor Regenerates

Having sustained a fatal fall from the Pharos Project radio telescope, the Fourth Doctor assures his companions that "it's the end, but the moment has been prepared for." Upon saying this, the Watcher, a manifestation of the Doctor's future who'd been following the TARDIS team around throughout the serial, appears and merges with the Doctor, allowing him to regenerate. As this happens, the scene is underscored by a medley of the Watcher's leitmotif and the show's title theme, representing the "death" of the Fourth Doctor and the "birth" of the Fifth. The end of Four's era (and the end of Season 18) is further hammered in by applying an electronic blur to Tom Baker's face in the closing credits.

How well does it match the trope?

5 (5 votes)

Example of:

Main / LeitmotifUponDeath

Media sources: