The one where Matthew Waterhouse throws up, Nyssa forgets what hydrogen is, and the crickety-cricket celery wearer makes his debut.
Previously on the big Dee-Dub, the Doctor took a nasty spill from disconnecting the Pharos Project's power cable, prompting a sudden regeneration. (It's a big one too — even his shoes regenerated!) Unfortunately, he doesn't take to it very well, and is in danger of turning senile; that is, unless he can get some rest and healing in the TARDIS' Zero Room, a sensory deprivation suite.
The freshly-regenerated Fifth Doctor wanders around his TARDIS with some regeneration amnesia, briefly and randomly adopting mannerisms from his past selves, constantly mistaking Adric for past companions, peeking into rooms and unraveling his scarf. The TARDIS is kind enough to hand her new Doctor a crickety outfit and a cricket room. Tegan just met the Doctor hours ago, and (though she took the whole new-body thing surprisingly calmly) even she realizes that he's gone batty. They get him into the Zero Room note , but he's only just stretched out (three feet above the ground) and closed his weary eyes when the TARDIS' Cloister Bell alarm starts up. This is annoying enough for us humans when we're tired from a hard day slinging data and just need a good night's sleep before an important meeting in the morning; imagine how much it must suck if you're tired from saving the world and dying and being born again, plus the alarm isn't for an 8 AM meeting but an urgent warning that your spacetimeship is headed into the Big Bang.
Tegan and Nyssa put their heads together (as usual, Adric is being difficult and unwillingly in league with the villain), consult the TARDIS manual and inexpertly shteer it to "Castrovalva: the Dwellings of Simplicity". Its brochure makes it sound like an alien day spa: the perfect place for a bit of R&R. The Doctor wakes up for a bit, and the TARDIS tries to help out by dumping a lot of random medicine on his head and providing him with a wheelchair. While spinning in circles in said chair and being extremely amnesiac, he instructs his companions on how to propel the TARDIS away from disaster by deleting rooms. Luckily, the control room doesn't accidentally get deleted. Sadly, the Zero Room does, so they have to improvise a new portable one out of the doors, which were the only part to escape jettisoning note .
Once they've landed and spent most of an entire episode carrying the Doctor through the woods, they discover that Castrovalva is... weird. It's built funny. All the books in the library are written in the same handwriting, even the very old ones. The quaint passageways always seem to lead to the same town square. Even more ominously, the kindly and wise elder statesman of the city is played by someone named "Neil Toynay", which of course is an anagram for "Tony Ainley", which means that the whole thing was an elaborate trap set by the Master! And they must escape Castrovalva as it dissolves into a puddle of M. C. Escher illogic around them.
Now that spells "regeneration trauma". No wonder the Tenth Doctor was bedridden and in need of a cup of tea after his regeneration. (And little wonder the Sixth Doctor spent his regeneration recovery trying to kill anyone and everyone around him.)
Eventually, the Doctor regains his memory, convinces the townsfolk to override their collective Weirdness Censor and defeats the Master. Also, it turns out that Tegan didn't steer the TARDIS at all - that was all the Master's doing. The Doctor pins a vegetable to his coat and happily heads over to the next adventure.
- Art Imitates Art:
- In crafting his storyline, Christopher H. Bidmead remembered two prints in the office of Graeme McDonald, the Head of Drama, whose optically illusory nature had irritated John Nathan-Turner who believed that "art should be there to soothe, not distract". These had been drawn by MC Escher, in which figures are seen to walk up or down all sides of a series of staircases, Belvedere (1958), in which the perspective of a building changes between floors, and Ascending and Descending (1960), in which a staircase endlessly loops back onto itself. Bidmead thought that an environment exhibiting these sorts of traits could complement a story which dealt with the mathematical concept of recursion, in which one member of a sequence is generated by one or more of the preceding members of that sequence.
- The shot used in this story of the town of Castrovalva sitting on a cliffside, and the name of the settlement, was inspired by a print by M. C. Escher. Later in the serial, the collapsing world of Castrovalva takes on a distorted appearance, reminiscent of Escher's surrealist work.
- Bizarrchitecture / Mobile Maze
- Chased by Angry Natives: You don't built a fortress on a impenetrable bluff if you welcome visitors. Zig-Zagged by the Castrovalvans themselves, who later reveal themselves to be a proud scholar race - underneath all the fur and feathers, of course.Doctor: ..."Library"? Books and stuff?
Shardovan: (dourly) Books are the principle business of a library, sir.
- Chekhov's Gun: Nyssa and Tegan pretend that the Doctor is still lying in the Zero Cabinet. They know the Master well enough to predict he'll spend hours crow-barring the cabinet open rather then sticking to his plan. "One long last look before I destroy him utterly!"
- At first glance, the self-changing tapestry is mere artwork. The Master aims to turn it into the galaxy's biggest 3D printer.
- Chekhov's Lecture: Tegan and Nyssa discuss recursion.
- Continuity Nod: The disoriented Doctor confuses his current companions for several previous ones, even going back to One's time when he calls Tegan "Vicki". He also takes on the mannerisms of the First ("I wonder, my boy, what you would do if you were me, hmm?"), Second ("Oh no! We've gone into the wrong part of the TARDIS! Jamie, you go back! When I say run, run!") and Third ("...always remembering of course not to reverse the polarity of the neutron flow"), suggesting a sort of dementia.
- The Doctor's conversation with Adric (shaking his hand as if they'd just met, much to Adric's confusion) also counts as this. Adric is holding part of the Fourth Doctor's costume, which the Fifth Doctor has been discarding in pieces to mark his path.Doctor: I left a waistcoat like that on... Ever been to Alzarius?Adric: I was born there, Doctor.Doctor: Really? It's a small universe, isn't it.
- The Doctor's conversation with Adric (shaking his hand as if they'd just met, much to Adric's confusion) also counts as this. Adric is holding part of the Fourth Doctor's costume, which the Fifth Doctor has been discarding in pieces to mark his path.
- Continuity Porn: Some pinpoint the first major Fan Wank moment in the Classic series as being the Fifth Doctor's post-regeneration trauma causing him to go through impressions of all four previous Doctors.
- Democracy Is Bad: Used for the purposes of a gag.
- Distracted by My Own Sexy: Averted this time around. The Fifth Doctor looks in the mirror, but his chief reaction is disappointment/alarm that the curls are gone.Doctor: That's the trouble with regeneration... you never quite know what you're going to get.
- Distressed Dude: Adric spends most of the story strung up in a web inside the Master's TARDIS.
- Easy Amnesia
- Establishing Character Moment: The Fifth Doctor comes across as very gentle, very naive, and very normal for the majority of the episode, but after about three-quarters of the story, the "that's democracy for you" line firmly establishes him as a Deadpan Snarker as well.
- Everybody Lives: Well, nobody real dies.
- Evil Wears Black: Subverted. Shardovan's the only Castrovalvan that wears black, which makes the rest of the characters suspicious...but he turns out to be a Red Herring.
- Fake Memories: Heck, the Castrovalvans have Fake History.
- Fake Town: This trope is in fact its major plotline. Castrovalva looks and feels like a city, except it's a trap set by the Doctor's frenemy, the Master, in order to trap the Doctor, but it ends up turning on the Master.
- Falling Chandelier of Doom: Shardovan swings from a chandelier and crashes into the web, freeing Adric and breaking the Master's illusion.
- Giggling Villain: Anthony Ainley is quietly chuckling to himself all through this episode and the last one.
- Gilligan Cut: The Doctor mentions how flying the TARDIS is difficult and you need to do more than flip a switch. Cut to Tegan, praying and flipping a switch.
- Giving Them the Strip: How Nyssa transitions out of her Traken princess garb to what becomes her standard outfit. She exits the TARDIS after swapping her fairy skirt for corduroy trousers (Sarah Sutton's own), presumably to make carrying the Doctor in his Zero Cabinet easier on herself. Then, over the course of trekking through the jungle with Tegan, she ends up losing her tiara and her stole to the exotic foliage.
- Glamour Failure: In truth, this was a barren jungle before the Master conjured up the city and its inhabitants.
- Heroic Sacrifice: Shardovan.
- Hidden in Plain Sight: The Master appears to be holding Adric captive in an undisclosed location elsewhere. The net is actually located right behind the tapestry, which explains how the Master could be in two places at once. The Master pulls this off twice: his TARDIS is camouflaged as the fireplace.
- Idiot Ball: Downplayed: Despite being a scientist, Nyssa has to look up what hydrogen on the TARDIS's console.
- I Die Free: Shardovan's Famous Last Words.Shardovan: You made us, Man of Evil - but we are free!
- Leaning on the Fourth Wall: When the Doctor first sees himself in a mirror and talks to himself, it looks like he's addressing the audience.
- Living Battery: Adric's block transfer computations are powering Castrovalva.
- The Load: Literally, in the Doctor's case. With the Zero Room lying in shambles, the Doctor and Nyssa contract a miniature version using a few leftover TARDIS panels. This makeshift Zero Room must then be wheeled all the way to Castrovalva. The Doctor promises that he will levitate within the box, thereby lessening the weight of it, but this (naturally) proves to be false as poor Tegan and Nyssa stumble around the jungle.
- Luck-Based Search Technique: The Doctor, still dizzy from his regeneration, bungles his first trip into the TARDIS and ends up the cricket room. Having shed most of his old clothes (and shoes) in the halls to avoid getting lost, he makes a jump for the cricket whites and gear on display. He's so taken with the result that it becomes permanent.
- Master of Disguise: This is probably the only serial in which the Master's disguise is effective and actually intended to fool the audience (rather than build anticipation for the Master announcing himself to the Doctor). Ainley's makeup and performance as the Portreeve is naturalistic and genuinely convincing.
- Mind Probe: The Master keeps Adric trapped in a hadron web that forcibly extracts Block Transfer Computations from his mind, and trying to force the Master out of his head seems to be pretty painful for the poor kid.
- Mind Screw: Consider the image on this page, if you will, if you wish to understand how wonky the realm of Castrovalva is.
- The Nth Doctor: Peter Davison makes his debut as the Doctor.
- Nice Hat: All of the Castrovalvans, but especially the Portreeve, who appears to be wearing a hat made of two Perspex boaters.
- No-One Could Have Survived That: The Master ducks into his TARDIS once his creations turn on him - but he's too monomaniacal to leave the web behind, so he gets tackled by the Castrovalvans as the city vanishes and buries them all (and his TARDIS) under solid rock. The Fifth Doctor doesn't address this, however, and even speaks of the Master in the present tense. He knows better.
- Not Named in Opening Credits: Tom Baker doesn't get credited for his (archived) pre-regeneration appearance.
- Our Graphics Will Suck in the Future: It turns out that the fantastically advanced TARDIS computer has a display that is outperformed by a ZX Spectrum. Justified in that later it turns out that the whole interface was a phony produced by the Master so that Tegan and Nyssa would think they were piloting the TARDIS.
- Perfect Pacifist People: The Castrovalvans who have evolved from a hunting society into a scholarly race. Justified in that it was all a trap by the Master, who knew that the Doctor would prefer to recover on a peaceful planet.
- Platonic Cave: The eponymous setting: inspired by and named for a lithograph by M. C. Escher, custom-made by the Master and Powered by a Forsaken Child, Adric.
- The Pratfall: When the wheelchair supporting the Doctor's sarcophagus tumbles into a creek, Nyssa is sent to fetch it and winds up somersaulting into the drink, losing her mantilla in the process.
- Reality Is Unrealistic: People have often joked about the Doctor's regeneration almost failing, when all that happened to him is falling off a satellite dish, compared with some of his other regenerations. Realistically, though, it's a surprise he could talk after that...
- Red Herring: The audience is clearly intended to believe that Shardovan (who is shifty and sinister and dresses all in black) is the Master. Probably intentional in-story as well. Also, the Doctor encounters yet another primitive tribe, only to discover that they're friendly intellectuals who were honoring a supposedly ancient tradition.
- Resurrection Sickness: The Fifth Doctor had it bad. Probably the worst of any, barring perhaps the Eighth Doctor's. Made worse considering that his ship was headed into the Big Bang while he tried to recover.
- Scenery Porn: The picturesque Castrovalvan countryside, which comprises a good deal of Part 2.
- Shout-Out to Shakespeare: In his hazy state, the Doctor quotes Hamlet:Go softly on!
- Significant Anagram: The above-mentioned anagram for Anthony Ainley.
- The Teaser: The first episode of Classic Who to include one of these (one of just four in total), which consists of a recap of the final moments of "Logopolis" with different music (a more uplifting soundalike of the original).
- Tempting Fate: It's hard not to cringe at Five destroying his predecessor's scarf, as if Peter Davison didn't have enough of an uphill battle to get the fans to accept him in the role.
- Tim Taylor Technology: The TARDIS manages to survive the Big Bang. After jettisoning some rooms first.
- Tomato in the Mirror: For the Castrovalvans, especially Shardovan.
- Trail of Bread Crumbs: The Doctor's companions aren't much use when it comes to navigating the TARDIS - though Five is, admittedly, foggy on the subject - requiring him to leave bits and bobs of the Fourth Doctor's clothing lying at intersections, so he can be found. Good thing that scarf was so huge. (Tegan uses her lipstick.)Tegan: (following string) Looks like the Doctor's coming unraveled in more ways than one.
- Villainous Breakdown: The Master has a meltdown after his precious web is destroyed. "My WEB! MYYYY WEEEEEEEEB!!"
- We Can Rule Together: The Master to Adric.
- Weirdness Censor: Nobody in Castrovalva finds the recursion odd until their attention is drawn to it.
- Wham Line: Shardovan in Part 4, when he works out what's been bugging the Doctor about Castrovalva's 500-year-old history books - "The books are old, but they chronicle the rise of Castrovalva... up to the present day."
- What Measure Is a Non-Human?: The Master treats the Castrovalvans as "creatures" he invented for his own uses and has no problem deleting Ruther once he tries to fight back. The Doctor, who sees the Castrovalvans as sentient beings, protests.