Written by Neil Gaiman.Hedgewick's World of Wonders is known as the greatest theme park in the galaxy. The Doctor takes new temporary companions Angie and Artie Maitland to the park for a fun day out (he's got a golden ticket and everything), but the TARDIS parks them there a few decades too late and the whole place has been shut down. Instead of the Spacey Zoomer and free ice cream, team TARDIS finds an army platoon that has been sent there (mostly to keep them out of everyone else's way) and a caretaker named Webley. The Doctor runs a Bavarian Fire Drill and pretends to be a high-up envoy of the emperor, who's been missing for a number of years. He decides to hang out with Webley for a bit just to show the kids a good time.Webley has an empty Cyber-suit in his home, which he uses as a parlor trick when he gets people to play chess with it. Inside is actually a little person nicknamed "Porridge" (Warwick Davis!) who quickly befriends Clara. Just as the whole gang is about to head back home, the Doctor realises that things are very wrong on this planet, and goes off to investigate, telling the kids to stay put. They don't, of course, and while Angie, Artie and Webley get kidnapped and put into a "walking coma" by the quickly revived Cyberman, the Doctor is infected by Cybermites (like Cybermats, only quite tiny) and turned into a magnificentlyLarge Ham in the process. The Cybermen were only looking for clever young children, like Angie and Artie, but a Time Lord is infinitely more useful. And they really didn't expect to find one here... after all, the Doctor has been deleting himself from history across the universe.The Doctor tells the Cyberplanner, who's taking over the Doctor's mind, that he could simply commit Heroic Suicide and regenerate on the spot to destroy the Cyberplanner's implants — and, via the Cyberiad network, every Cyberman it controls. Instead, they battle it out both in the Doctor's subconscious and over a game of chess. The Doctor's fully aware that the Cyberplanner will betray him no matter who wins, but does what he can to protect the children. Meanwhile, Clara takes full advantage of the Doctor's Bavarian Fire Drill and takes charge of the platoon. She spends most of it trying to prevent the soldiers from blowing up the planet, since that's been their modus operandi ever since the last war with the Cybermen. They even blew up the Cybermen's entire galaxy. Porridge tells Clara that he feels tremendously guilty over that — because no matter how much he tries to think about all the lives that were lost that day, all he can really bring himself to care about is the poor man who had to push the button.The Doctor temporarily manages to short-circuit his cyber parts using his golden ticket and tries to avoid Clara's difficult questions about the things the Cyberplanner has been telling her — about her being "impossible", for one. When he finally manages to use the platoon's gadgets and his own screwdriver to remove his cyber parts and gets the kids out of their comas, Angie points out what's been glaringly obvious to her all along: Porridge is the missing galactic emperor. Porridge explains that his off-planet army can transmat them all out within seconds, so blowing up the planet was actually a pretty viable idea all along. And he's so impressed by Clara's leadership skills that he asks for her hand in marriage. She declines, to Angie's great annoyance.The Doctor drops the kids off back home, and Clara joins them, telling the Doctor he can pick her up again next Wednesday.
Adaptive Ability: The Cybermen adapt very quickly to whatever is thrown at any one of them, since they are all linked in the Cyberiad. It's hard not to be impressed by software patches that are able to fix hardware problems.
Alien Sky: Even Angie is impressed for a moment, when it's shown they're not actually on Earth's moon.
The Assimilator: It seems to have become the main strength of the Cybermen. A particularly ghastly aspect is that people seem to keep their personality for some time as they get upgraded.
Porridge: It's hard to fight an enemy that uses your armies as spare parts.
Author Appeal: If you hadn't seen Neil Gaiman's name in the opening credits, you'd still know that this episode was his work. That, or a huge homage to him.
Ax-Crazy: The Cyber-Planner, in contrast to the regular emotionless footsoldiers, is insane and about thrice as hammy as the Doctor.
Battle in the Center of the Mind: Simultaneously played straight and subverted; while the Doctor and Mr Clever are fighting for the Doctor's mind much of the actual battle is done in the real world through a game of chess.
Bittersweet Ending: The Cybermen are defeated, but Webley and several of the soldiers are dead, the planet was blown up, a Cybermite remains, and Porridge is forced back onto the throne he hates.
Blessed with Suck: Porridge is Emperor of the Universe, a job which no-one wants, including him.
Bratty Teenage Daughter: Angie is rather insufferable, though this is never commented on by the other characters. To the Cyberman who's abducted her: "Put me down! I hate you!"
Brick Joke: Clara is forced to sign a requisition form just to get the Earth-Shattering Kaboom controller out of the soldiers' hands. Then Mr Clever manages to snatch it and destroy it, and how do the soldiers handle the news?
The proper return of the Mondasian Cybermen since 1988. note By Word of God, the technology is a merger of Cybus and Mondas-based Cybermen, though the story uses a lot of elements and inspirations from the 1960s incarnations, and appears to follow the Cyber-Wars mentioned in later, but pre-Cybus, seasons Previous appearances going back to the "The Pandorica Opens" have been confirmed to be Mondasian Cybermen by Word of God, but the costumes weren't updated (or just had the Cybus logo removed). These ones actually have updated costumes.
The Cavalry: The imperial flagship that appears at the end and beams everyone safely aboard.
The Chains of Commanding: The reason the emperor has been in hiding for such a long time. At the end he casually offers the role to an underling who turns it down, which he concedes is the right choice.
The golden ticket turns out to be quite literal — enough to temporarily fry the Cyber-Planner.
The galactic penny that Webley gives to Angie is what allows her to identify Porridge as the missing Emperor.
Chewing the Scenery / Large Ham: Matt Smith after Mr. Clever is put in the Doctor's head. If you thought his usual performance was over the top...
Conservation of Ninjutsu: For a while, one Cyberman does better than three million of them. Justified as (1) he's taken over about half the Doctor's brain, and (2) this version of the Cybermen apparently use processing power from one hive mind; the less that are operating at once, the more competent and intelligent they can be as individuals.
Children's minds are used for the Cyber-Planner because their brains have more potential. A similar logic was used by the Daleks in creating their Battle Computer Interface. The Krillitanes used the same principle in "School Reunion".
It's not the first time a strong-willed host manages to retain their personality while cyber-converted.
Cranial Processing Unit: Zig-zagged. The stun gloves work by application to the back of a Cyberman head, but a Cyberman is shown to be able to purposefully detach its head without loss of function.
Did Not Think This Through: The Doctor's plan to fake his death and remove all evidence of himself from history. As the Cyberplanner notes, it's pretty clear to figure out he's still alive and he exists, due to the "giant Doctor-shaped hole" left behind with nothing to fill it. The Doctor seems to realise this.
Distracted by the Sexy: The Doctor refers to Clara as "a mystery wrapped in an enigma squeezed into a skirt that's just a little bit too... tight." He then catches himself thinking aloud and snaps out of it.
In the opening scene, Angie and Artie are convinced they're on the moon, even though the obvious signs that they aren't are literally on the walls off-camera. They also didn't seem to find anything odd about being able to breathe on the moon.
At a critical moment, the Cyber-Planner is too busy with the Doctor's mind games to notice an armed man enter the room. It hesitates to make the Doctor suffer and gives the newcomer time to act.
Angie acts like a Bratty Teenage Daughter at first, but she's the only one to notice the Emperor statue is just a taller version of Porridge.
Clara: Full of surprises.
The Doctor's fully aware that the Cyber-Planner won't honor their bargain, he was just stalling till he could come up with a suitable Indy Ploy.
Clara promptly takes away the Planet detonator, repeatedly reminds the soldiers to not blow the planet up, chooses a goofy castle as a hideout because it still has the defenses of a castle, and knows that following the Doctor's orders are the most likely way for them to survive. She also thinks to check if the Cybermen can fly, when coming up with her plan to electrify the moat.
Godzilla Threshold: The Adaptive Ability of the Cybermen has made them so dangerous that standing orders demand the immediate destruction of the entire planet should the first engagement with a Cyberman fail to kill it. In the backstory, this happened to an entire galaxy because they couldn't beat the Cybermen any other way.
The Doctor: Er, a bit of a good news, bad news, good news again thing going on. So, good news, I've kidnapped the Cyberplanner and right now I'm sort of in control of this Cyberman. Clara: Bad news? The Doctor: Bad news, the Cyberplanner's in my head. And, different bad news, the kids are, well, it's complicated. Clara: Complicated how? The Doctor: Complicated as in walking coma. Clara: Please tell me you can wake them up. The Doctor: Hope so. Clara: Other good news? The Doctor: Well, in other good news, there are a few more repaired and reactivated Cybermen on the way, and the Cyberplanner's installing a patch for the gold thing. No, wait, that isn't good news, is it. Er, so, good news, I have a very good chance of winning my chess match.
The Big Finish Eighth Doctor audio episode "The Silver Turk" also features Cybermen playing board games. Both episodes reference the original mechanical turk (a supposed chess machine which was actually operated by a person inside). That makes the second direct reference in this season to an Eighth Doctor audio from that specific storyline, after "Hide" name-checked the story "The Witch from the Well" (which comes directly after "The Silver Turk").
It also continues the running references in season 7 to Big Finish Doctor Who, most notably the Eighth Doctor's adventures.
Ironic Echo: "That's cheating!" "Just taking advantage of the local resources."
I Shall Taunt You: At the end of his chess game, the Doctor claims he can win in three moves. This is such a bare-faced lie that the Cyber-Planner borrows the computing power of his entire army to definitively prove the Doctor's full of it. This allows Clara and the soldiers to escape an otherwise-imminent demise and the Doctor to modify a pulse glove to free himself. For the record, the Doctor was indeed lying. He did not have mate in three moves. He had itin six.
Jekyll & Hyde: The Cyberplanner is essentially an Evil Counterpart of the Doctor who shares a body with him, taking over periodically before the Doctor is able to regain control.
Kind Restraints: The Doctor insists on being tied to a chair in front of the chess board (they're to leave his hands free to play chess).
King Incognito: Porridge. As with the best examples, he even serves food to his soldiers.
Large Ham: Mr Clever could feed the entire third world for months with the amount of ham he's exporting.
A Million Is a Statistic: Porridge admits that he feels bad about feeling sorry for the person who had to press the button to destroy a galaxy, when he doesn't feel as sorry for the billions of trillions who lived in it. Considering Porridge is the Emperor, he's presumably a descendant of the person who, figuratively if not actually literally, pressed the button.
Moral Myopia: Mr. Clever, despite all his general ruthlessness, complains that the Doctor's plan to get rid of him is cheating because he wasn't beating him at a fair game of chess.
Nice Job Breaking It, Hero: The Cybermen are able to wake up because the Doctor brought children to the planet, and they alone make suitable processors. Then it turns out the Doctor has even more capacity...
The Doctor used to be immune to the cyber conversion on account of being alien... up until this episode, where they're improved the process to work on any lifeform.
The Cybermen take this trope up a notch with their Adaptive Ability by being able to shrug off methods that would have killed them left and right. In particular, the electrified moat only briefly stops one until it adapts, and the gun that vaporized one Cyberman only gets off two more shots before they're completely immune.
Running Gag: As he did with Rory, Eleven takes a cheap shot at Clara's nose. Also counts as Hypocritical Humor, since Eleven's nose isn't exactly petite (it's possible he's lashing out about all the chin jokes).
The Cyber-converted Doctor calling himself Mr Clever is a shout-out to Riddley Walker.
The chess-playing Cyberman at the beginning is a reference to The Mechanical Turk, an eighteenth-century automaton that, like the Cyberman, was actually a fake operated by a chess-player hidden inside the cabinet, which used magicians' tricks to make the space available appear smaller than it actually was (yes, it was actually Bigger on the Inside).
Clara is told that if she has a chance to become queen of the universe, she should say yes.
A human empire with an "Imperial Guard" that casually destroys whole planets to deal with alien infestation and their Emperor is virtually worshiped? Even the uniforms bear a substantial similarity. And they wield laser weapons. As a Mythology Gag within a Shout-Out, The Emperor's full name is Emperor Ludens Nimrod Kendrick Cord Longstaff the 41st.
Silent Antagonist: Barring Mr Clever, the Cybermen barely say anything at all in this episode, other than "Upgrade in Progress" when a) converting others into their own or b) altering themselves so that a previously fatal weakness becomes muchless so.
Something Only They Would Say: Clara does this with the Doctor. When he offers Ship Tease as a response, she slaps him to get the real Doctor back. Even if he actually felt that way, he'd never admit it.
Stompy Mooks: The new models are a little more streamlined, but still pull off the ominous march. That said...
Stop, or I Shoot Myself!: When the Cyber-Planner speaks with the Doctor in his mind, the Doctor half-threatens to regenerate to stop him; not only ending his eleventh life, but frying any Cyber-related component in his head. The Cyber-Planner announces stalemate.
Super Speed: The Cyberman who snags Angie does this, moving so fast the Doctor and the soldiers appear almost standing still.
Tagalong Kid: Clara has to bring Artie and Angie along for an adventure... or they tell their father their nanny's a time traveler.
Virtue Is Weakness: The Cyber-Planner scoffs at the Doctor's emotions, and his willingness to make sacrifices to protect the children.
Weaksauce Weakness: The infamous gold allergy. Most of the Cybermen have evolved beyond it, but the cyber-mites' operating system still contains this glitch buried deep within the source code. This causes the tech to be temporarily scrambled by gold, at least until the Cyber-Planner manages to install a software patch.
Averted when we a Cyberman is seen walking into water, a common example of this trope for robots, but all it does is slow it down before it No Sells it.
Wrong Genre Savvy: The Doctor is initially confident that he has little to fear from the Cybermen, since they assimilate humans, not aliens. Cyber!Webley confidently informs him that they've since adapted to use almost any form of life.
You Are in Command Now: A non-fatal version. The Doctor, having used the psychic paper to con his way into authority over the local military contingent, makes Clara their commander so they won't immediately destroy the planet. Becomes the fatal version pretty quickly.