Nightmare in Silver (TV story)

Nightmare in Silver was the twelfth regular episode of the seventh series of Doctor Who produced by BBC Wales.

Synopsis
Hedgewick's World of Wonders: the perfect theme park day out. And ground zero for a deadly silver resurrection.

Plot
The doors of the TARDIS open and four heads pop out: The Doctor, Clara, Angie, and Artie. The Doctor welcomes them to Hedgewick's World of Wonders, the biggest and best amusment park there will ever be! Clara and Angie look sceptical, with Angie declaring that his (The Doctor's) "stupid box" couldn't get them to the right place. Indeed, they appear to be on the Moon, with the Earth suspended in the background and a plastic-looking American flag stuck in the dirt. The Doctor repeats that it's not the Moon, looking rather annoyed.

Suddenly, a rock opens and a short man in a top hat peeks out. He asks the group if they were Dave's Discount Interstellar Removals, who were apparently six months late. A shout goes up and the man disapears. A military platoon comes storming out and demands identification from the travelers. The Doctor flashes his Golden Ticket, and when that doesn't work, whips out the Psychic Paper. The captain recognizes him as the Imperial Consort, and asks for news of the Emperor. The Doctor dismisses the platoon, and the top-hat man comes out again. He leads them into the desolate, formerly grand amusment park, and then into his attraction: Webley's World of Wonders.

He introduces himself as Embassario Webley, and shows them his waxwork attractions of famous and infamous beings. He asks Artie for a game of chess, and leads him to a covered display. Webley declares it a dangerous enemy, long deafeated, but now returned to destroy him. He unveils the display to reveal a Cyberman at a chess board. The Doctor yells to get down as the Cyberman powers up. Webley reassures them that it's completely harmeless,telling them that there are no more living Cybermen. He cites his display as "the six hundredth and ninety-ninth wonder of the universe", and a master at chess, despite the fact that it is an empty shell. Angie guesses at first that it is controlled by magic, Webley agreeing with her. He offers five Imperial shillings for a penny if Artie can beat the Cyberman at chess. Artie offers a sandwich, and Webley accepts. He shows that the shell is free of all devices, while the Doctor scans it with the sonic.

Artie begins the match, the Doctor criticizing his moves. Webley offers a silver penny to Angie if she can figure out how it works. She guesses that it's done with mirrors, prompting the Doctor to praise her cleverness. He deduces that it's being controlled by a man inside the box, named Porridge, and Webley gives Angie a silver penny.

Webley shows off the rest of his Cyberman collection, as well as a wax figure of Emperor Ludince Nimrod Kedbrig, etc. the 41st, Defender of Humanity and Imperitor of Known Space. Clara comments that he looks rather full of himself, and Porridge warns her not to say such things, fearing their wrath. The adults lead the kids off to the Spacey-Zoomer ride, while Angie stays. She looks at her penny, and compares it to the wax figure, before Artie drags her off.

The Spacey-Zoomer ride turns out to be an anti-grav ride, letting the children fly and float around. Clara takes pictures of them. As Porridge lets them down, Artie declares that the most fun ride ever, while Angie judges it to be okay. Clara wants to get the kids home, but the Doctor doesn't want to leave. He finds "funny insects" that he wants to investigate, and forces everybody to stay longer. The kids crash on couches in Webley's house, and adults go off, with the Doctor warning the kids not to wander off. The terrified kids settle into the couches.

Webley resets his chess board while eating the sandwich he won off of Artie. Suddenly, the Cyberman grabs his hands. As Webley struggles, the "funny insects" that resemble cybermats crawl over his body. The Cyberman informs him that he will be upgraded. The insects light up and begin upgrading Webley as he screams.

Angie declares the future to be stupid, complaining that there isn't even phone service. She leaves, despite protests from Artie, as the insects crawled over Clara's phone.

Porridge explains the Cybermen to Clara, citing their long wars with them. He said that human armies couldn't win, especially since the Cybermen used their dead for spare parts. Clara reasons that the humans must have won, or Porridge wouldn't be standing there, so she wants to know how. Porridge points to a section of the sky and ask Clara what she sees. She says nothing, just black, no stars. Porridge tells her of the Tiberian Spiral Galaxy, consisting of a million star systems, a hundred million worlds, a billion trillion people. The Tiberian Spiral Galaxy had to be blown up to destroy the Cybermen. Porridge comments that he feels like a monster: Instead of mourning a billion trillion deaths, he feels sorry for the person who had to press the button.

The Doctor interrupts and ask Clara if she told Angie she could go to the barracks. Clara says that she did not, then realizes with horror that Angie had wandered off anyway. In the barracks, the platoon are trying to fix their systems, when Angie appears, loudly declaring that she was bored. The captain asks Angie where her sister was. Realizing that she meant Clara, Angie denied that they were sisters, calling Clara stupid and saying she was talking to Porridge. The captain pulls Angie off for a talk.

Meanwhile, Artie wanders off, looking for a light switch. The house makes noises and creaks, scaring him. He finally finds the lights. Suddenly, a cyberhand claps over his mouth. Back at the barracks, Angie is telling the captain about Porridge when Clara storms in. Angie yells at Clara to leave her alone. Without warning, an upgraded Cyberman appears in the doorway. The captain declares attack formation, and the platoon fights feebly. The Cyberman, able to move faster that the eye could see, dodges the bullets, leaps over the makeshift barricades, and captures Angie. Clara tries to go after Angie, being stopped by the Doctor. He promises that he will get her back, then addresses the captain. He realizes that the platoon doesn't do much fighting. The captain tells him that they are a punishment platoon. The Doctor invokes his "power" as "Imperial Consort", stripping the captain of her rank and giving it to Clara. He tells Clara not to let them blow up the planet, to get to somewhere defensible, and to stay alive. The Cyberman brings Angie to a room, where she finds her brother in a waking coma, controlled by a Cyber earpiece. In the corner is a partially upgraded Webley. In a cybernetic version of Artie's voice, her brother informs her that she will be upgraded. Realizing what is going to happen, she screams. Webley raises his cyber hand in a shushing gesture.

Meanwhile, Clara in her new role as commander, scrounges up all their resources to build a offense against the Cybermen. The captain takes her to a map of the amusment park, looking for the most defensible place in the park. They decide on Natty Longshoe's Comical Castle as their base, with a drawbridge and a moat. The captain informs Clara that the platoon can deal with one Cyberman, but there are protocals that they must follow if they cannot find and destroy it: specifically to blow up the planet. Clara rejects this with disgust, and orders her to move the platoon and their weapons to the castle, supported by Porridge.

The Doctor returns to where he left the children, finding them missing. He spots a cyber insect on a display. Regarding it, he informs whoever is watching the feed that the children are under his protection, and he is coming to get them. Then he informs the machine that "[it] is beautiful!", sonics it, and studies it. He comments that it wasn't even a Cybermat anymore, but a Cybermite. He uses the sonic to tune into the local transmat, bringing himself to the children. He rushes over to them, and realizes with horror what has happened to them and Webley. His brain fully converted, Webley speaks for the Cybermen. He informs the Doctor that they needed children, and declares him the "savior of the Cybermen".

The platoon approaches the castle, and the captain tries to convince Clara to blow up the planet. Porridge puts in a plea to let them hunt the Cyberman. Forcefully, Clara declares that the only reason she was alive is because she listened to the Doctor. She asks if they can guareentee that her children will be returned to her alive and unharmed, and then asks if they trust the Doctor. The captain asks if the Doctor knows what he his doing, and Clara says that she wouldn't go that far.

Webley tells the Doctor of the Cybermen. As the battle raged between humanity and the Cyberiad, they built a bunker to repair their damaged units. They needed children's brain to build a new Cyberplanet, as a child's brain has infinite potential. However, now that the Doctor is there, they have no need of the children. The Cybermites have been scanning his brain, and it is quite remarkable. The Doctor scoffs, telling them that he is useless to the Cybermen: they can only convert humans. CyberWebley tells him that that is no longer true. Their upgrades enable non-human conversion as well. He throws Cybermites on the Doctor, which incorporate him into the Cybernetwork. He becomes the Cyber-Planner, with non-human brain power to dream up ideas to strengthen the Cyberiad.

He takes stock of his body, noting the unfamilar systems and remarkable brain power. The Doctor, locked away in his mind, jerks back to himself and yells at his Cyberself to get out of his mind. The Cyberplanner is rummaging through his knowledge and memories to get information to upgrade the Cybermen. Inside the Doctor's mind, the two meet. Rather in a Jekyll and Hyde manner, the two wage war for control, the Cyberplanner using his memories to torment the Doctor. The Cyberplanner finds delight in his cleverness, realizing that there is information on the Time Lords available. The Doctor blocks it all but information on regeneration. He threatens to regenerate right then and there, to burn out the Cyberplanner. He doesn't want to, unsure of what he'll end up with next, but acknowleges that he could do it. The Cyberplanner declares a stalemate, concluding that they are too well balanced. One must take over. Each controls 49.881% of the brain, leaving .23 % unclaimed. The Doctor challenges the Cyberplanner to a game of chess, winner takes all. If the Cyberplanner wins, he gets the Doctor's mind. If the Doctor wins, he gets his mind back, the children are freed, and nobody dies.

Missy takes guard of a corridor. She notices a shadow, and reports it as possibly a Cyberman. Frightened, she hides. The Cyberman steps out of the shadows and detaches its hand. It crawls over to Missy and drags her out of her hiding place.

Back at base, the platoon realize that the Cyberman is on its way. She demands to be shown any and all weapons. There is only one anti-cyber gun, a miracle since the Cybermen went extinct a thousand years earlier. She shows them hand pulses, a much more advanced version of the electromagnetic bomb invented and wielded by Mrs. Moore in the Cybus attack on alternate-London in 2006. (TV:The Age of Steel) Like its predecessor, the hand pulse is able to disable a Cyberman on contact. Finally is the weapon to implode the planet. Clara takes the remote control from the captain, but the captain informs her that it is set to respond to her voice only. Clara orders her to detonate the device only when she directly orders her to. The captain challenges Clara's command, declaring she will follow her own orders. Clara asserts her authority, and signs for the remote control.

The Doctor and the Cyberplanner begin their game. While they play, the Cyberplanner asks the Doctor why the Cyberiad has no record of him. He then realizes that the Doctor purposlly erased himself from history, noting that he could be reconstructed from the holes he left. The Doctor acknowledges that and says he'll work on that. The Cyberplanner rails against him, telling the Doctor that he cannot win against him. The Doctor counters with his knowledge of early Cybermen. Their codes can be scrambled by cleaning fluids and gold. He then slaps on the cyberpatches his Golden Ticket, temporarily scrambling the circuits. He comes back to himself, collects the chess board, and brings the children and CyberWebley to another room.

The captain and Porridge are discussing a secret regarding Porridge. She talks about guarding the old Emperor, and how she knows. Clara interrupts, asking why it was necessary to blow up a whole planet just to get rid of one Cyberman. Porridge says there are ways to kill a Cyberman, but they don't always work. Blowing up the planet is the only surefire way to do it. The captain says that she was sent to the punishment platoon because she didn't follow orders, and that she can make up for it now. She declares that she will do what she was born to do: live for the Empire, fight for the Empire, die for the Empire. She begins to voice-activate the weapon, identifying herself as Captain Alice Berry. As Clara tries to stop her, she is shot by the Cyberman.

Clara decides to go on the offensive, otherwise facing death. The platoon moblizes with hand pulses and the anti-cyber gun. The members of the platoon launch sneak attacks on the Cybermen, with limited success. The Cybermen take some of the force and put them in a waking coma, which are then deactivated by the pulse.

The Doctor approaches the castle with the children and CyberWebley in tow. He raises the chessboard defensively, with pleas not to shoot. Clara comes out with the anti-cyber gun and the Doctor greets her. She asks if the kids are all right, and when the Doctor fudges, she cocks her weapon. The Doctor rattles off his news: he kidnapped the Cyberplanner, which is in his head. The kids are in a walking coma, which he may or may not be able to correct. There are more cybermen active, and the Cyberplanner is installing a gold patch. He asks for a table and for somebody to imoblize him (except for his hands).

The Doctor, now tied to a chair, removes the gold sheet from his face. The Cyberplanner reemerges, telling Clara that the Doctor's chances of winning are low. The Cyberplanner taunts Clara, mocking the Doctor's previous incarnations (with his catchphrases such as "Fantastic!" and "Allons-y!"). He looks at her with interest, telling Clara that she is the impossible girl, and was the object of the Doctor's interest. She asks why she is the "impossible girl". As the Cyberplanner continues to rattle on, the Doctor moves his hand, writing "HIT ME!" on the notepad beside the chess board. Clara obliges, delivering a stinging slap. The Doctor thanks Clara, who then repeats her question, which he deflects. Clara demands to know the stakes at hand. The Doctor explains the stakes, and elaborates that the Cyberplanner will probably break his promise anyway. She begs the Doctor to fix Angie and Artie. He says that they're just in standby mode, which is not reassuring to Clara. He then elaborates that they are more likely to leave alive than she is. Sensing the change in control, she surmises that the Cyberplanner said those words. He threatens her immediate death, and she leaves to prepare the platoon for the coming onslaught.

Clara discusses their weapons, which are minimal at that point. Spotting a cable, she cleverly devises a plan to electrify the water in the moat. They drop the cable into the water, turn on the power, and raise the drawbridge to force the Cybermen to cross the water.

The Doctor's game continues. Inside his mind, the Cyberplanner awakes the legions of Cybermen hidden in the barracks. Inside the citadel, the platoon prepares their defense. Porridge gives Clara a bowl of soup to warm her up. The Doctor calls out for Clara, and she goes to check on him. The Doctor cheerfully asks her for a rundown on their weapons, with keen interest in the planet-imploding bomb. She shows him the remote trigger, which he tries to take possession of. She snatches it away from him, suspicious of who really is in control. The Doctor says the Cyberplanner is hibernating, but Clara doesn't buy it. She tells him to tell her something only the Doctor knows. Looking rather sincere, the Doctor begins to tell her that he is falling in love with her. He moves to kiss her, but Clara slaps him again. The Doctor comes to himself, overtaking the Cyberplanner's tricks. He asks her how she knew it wasn't him, and she says that whether or not what the Cyberplanner said about the Doctor's feelings were genuine, the Doctor would rather die than say it out loud. She tells him to finish the game, and the Cyberplanner grabs her hand, wresting the remote control from her grasp and destroying it. The Cyberplanner roars, ordering the attack to commence.

Clara and the platoon ready their attack with the five hand pulses and the nearly empty anti-cyber gun. The Cyberplanner declares endgame and moves to finish the Doctor. The Cyberarmy begins to assault the castle. One steps into the moat and is apparently electrocuted. The platoon celebrates, but then the Cyberman upgrades itself. The patch is spread through the ranks, and the Cybermen continue. Clara gives orders to defend the castle, and tells Porridge to keep himself safe. Two soldiers shoot down the first Cyberman, but balk as more come through. Porridge grabs the bomb, muttering that he should have destroyed the planet when he had the chance.

The Cyberplanner taunts the Doctor, offering him one more deal. If he sacrifices his queen in five moves, he'll release the children and take the Doctor's mind. The Doctor accepts the deal and Angie and Artie are released. The Doctor appears to have lost, but the children are free. The Cyberplanner taunts him once more, telling him how foolish he was to have pointlessly sacrificed himself for two human children. He mockingly asks the Doctor if he thinks that the death of the children will affect his relationship with Clara. CyberWebley moves to kill the children, but Porridge slaps a hand pulse onto his leg and kills him. Angie awakes and the Doctor tells her to look after Artie.

The platoon are losing the battle. They are out of weapons, and the Cybermen's continual upgrades are proving to be more than a match for the ragtag soldiers. The Doctor taunts the Cyberplanner, telling him that sacrificing his queen was the best move he could have made. The Time Lords invented chess, and the Doctor has cleverly set up a trap that will give him checkmate in three moves. The Cybermen appear to be overwhelming the platoon, but as they are about to delver the killing blows, the Cyberplanner pulls in their resources, giving him extra processing power. It saves the lives of Clara and the rest of the platoon, but puts the Doctor at a serious disadvatage. As the platoon makes their last stand, the Doctor adjust his bowtie and begins his endgame. Move One: Turn on sonic screwdriver. Move Two: Activate pulse. Move Three: Apply pulse. With some resistance from the Cyberplanner, the Doctor slaps himself with the hand pulse and destroys the Cybercircuitry in his body.

Clara rushes in to find the Doctor completely back to himself. He ask her to untie him, but Clara tests him by asking him if he thinks that she is pretty. He tells her that she is too short, too bossy, and her nose is too funny. Convinced, she cuts him loose. The Doctor decides that they need to blow up the planet to destroy the Cybermen. It seems impossible since the captain is dead, but Angie cleverly deduces that Porridge can voice activate it, since he is the Emperor. She figured it out by the image on the coin and the exaggerated waxwork. Porridge confirms it, saying he doesn't want to be Emperor, but after some convincing words from the Doctor, he activates the Dessolator. The Imperial ship warp-jumps them from the planet, including the TARDIS. The bomb ticks down, and the planet blows up, taking the Cyberiad.

Porridge remarks that he liked being normal: not an emperor of a thousand galaxies, not lonely. Clara says that he doesn't have to be lonely, and he agrees, proposing to her on the spot. Porridge makes a convincing argument, which Clara declines gently. Angie calls her stupid for not saying yes, loudly declaring that one day, she'll be Queen of the Universe. Porridge affectionately tells them to leave.

As the children leave the TARDIS, they thank the Doctor for their adventure. The Doctor leaves Angie with a parting gift from the TARDIS: a new phone. Angie apologizes for calling the TARDIS stupid, and bids goodbye to "Clara's boyfriend". Clara thanks him for the adventure and for saving everybody's lives, then bids him goodnight. She says "See you next Wednesday!", leaving the Doctor a little flustered and wondering who exactly she is, calling her "the mystery, wrapped in an enigma, wrapped in a skirt that's just a little too tight."

Back on the imperial ship, the Emperor asks if there was any Cybertech remaining, then flies his ship home, with a floating Cyberhead winking in the starlight.

Cast

 * The Doctor - Matt Smith
 * Clara - Jenna-Louise Coleman
 * Angie - Eve De Leon Allen
 * Artie - Kassius Carey Johnson
 * Webley - Jason Watkins
 * Porridge - Warwick Davis
 * Captain - Tamzin Outhwaite
 * Beauty - Eloise Joseph
 * Brains - Will Merrick
 * Ha-Ha - Calvin Dean
 * Missy - Zahra Ahmadi
 * Cyberman - Aidan Cook
 * Voice of the Cybermen - Nicholas Briggs

Alien Species

 * The head of a Uvodni and upper body of a Blowfish can be seen on display inside the room housing the chessboard.

Cybermen

 * The Cyber-Wars lasted 1,000 years. The planet Hedgewick's World is on was used to hide 3 million Cybermen and repair them.
 * Whilst not being able to convert non-humans in the past, the Cybermen can now process creatures like Time Lords, at least partially.
 * The "Cyberiad" refers to collective consciousness of the Cybermen.

The Doctor

 * Whilst under possession by the Cyber-Planner, the Doctor mimics the Ninth Doctor's accent and catchphrase of "Fantastic", as well as the Tenth Doctor's of "Allons-y".
 * When the Cybermites take over, the Doctor lets them see the regeneration power, by showing him his previous incarnations, plus the regeneration from his tenth to his current self. He claims that he can regenerate at will.
 * The Doctor has been erasing himself from history, leaving a hole in the Cybermen's records that used to be him.

Clara

 * It is suggested that the Doctor and Clara meet on Wednesdays for their adventures, as opposed to Clara being in residence aboard the TARDIS.

Games

 * The Doctor claims that the game of chess was invented by the Time Lords.

Cultural references from the real world

 * Porridge is inside an undefeated "automated" chess player. This is very similar to real-world the Turk, who was too exhibited as an undefeatable chess-playing machine, but was actually controlled by a man inside.
 * Interestingly, the Turk was the inspiration for the Clockwork Droids. (TV: The Girl in the Fireplace)

Story notes

 * The episode's title, Nightmare in Silver, is reminiscent of Silver Nemesis, in that, in both cases, the "Silver" is referring to Cybermen.
 * A working title for the episode was The Last Cyberman.
 * The Cyber-Doctor answers to Clara's question of "More Cybermen?" with "They're waking from their tomb right now." which is a possible reference to the television story TV: Tomb of the Cybermen.
 * Subsequently, the Cybermen exiting their tombs mirrors the cliffhanger of Earthshock Part 3 when three rows of Cybermen march towards the camera. It's also very similar of the scene where the Cybermen come out of their tombs in The Tomb of the Cybermen.
 * When the Doctor lets the Cyber-Doctor access his memories on regeneration, his previous ten incarnations are seen. Each image of an incarnation is taken from photograph stills used as promotional material during the respective actors' tenures.
 * The Cybermen's ability to adapt to attacks is reminiscient of the Borg from Star Trek: The Next Generation. Additionally, the Borg used nanotechnology to convert individuals, similar to the cybermites, and Webley's cyber-appearance is reminiscient of the Borg's "half machine, half human" face. And as of "Star Trek: First Contact" they, like these Cybermen, assimilated new members by use of something coming out of their wrists.
 * The Cyber-Doctor imitates the Ninth Doctor and says "Allons-y" like the Tenth Doctor.

Ratings
to be added

Filming locations
to be added

Production errors
to be added

Continuity
Angela Price invented an electromagnetic bomb that destroys Cybercircuitry, and may be a precursor to the hand pulses. (TV: The Age of Steel
 * It is never made clear whether these Cybermen are of the Mondasian or Cybus variety, although they use the phrase "upgrade" and two of Webley's Cybermen being similar to the ones from Closing Time with his third having the Cybus logo like the ones from The Pandorica Opens. Webley's explanation that the Cybermen have adapted and that the new model will be unstoppable may hint that the two types of Cybermen have encountered each other and merged their technology. This would explain why Cybus-like versions had Mondasian ships in The Pandorica Opens and A Good Man Goes to War, why one of Webley's models have the Cybus logo, and why the Cyber-Wars lasted longer than has been previously stated.
 * The Doctor can play chess. (TV: The Sun Makers, The Androids of Tara, The Curse of Fenric, The Wedding of River Song). Also, the Time Lords inventing chess was a query first considered by the Second Doctor. (PROSE: Dreams of Empire)
 * This is not the Doctor's first encounter with a Cyberman purported to be an automated game-playing machine. When the Eighth Doctor encountered the Silver Turk, a Cyberman, it too attacked its 'controllers'. (AUDIO: The Silver Turk)
 * The Doctor mentions the Cybermen's weakness to gold (TV: Silver Nemesis) and cleaning fluid. (TV: The Moonbase)
 * Two Impact suits can be seen. (TV: The Doctor, the Widow and the Wardrobe)
 * The Doctor says the children are under his protection. (TV: The Bells of Saint John)
 * Angie and Artie Maitland travel in the TARDIS, as they had previously blackmailed Clara into taking them along. (TV: The Crimson Horror)
 * The Tenth Doctor's regeneration is seen. (TV: The End of Time).
 * Several creatures from previous episodes are seen in Webley's room. This includes an Uvodni head, (TV: Warriors of Kudlak) a Blowfish head, (TV: Kiss Kiss, Bang Bang) a Shansheeth head, (TV: Death of the Doctor) a Chameleon, (TV: The Faceless Ones) a dummy, (TV: The God Complex) and several alien from Sun-singers of Akhet, including an Ultramancer, a Pan-Babylonian and a Lugal-Irra-Kush (TV: The Rings of Akhaten).
 * The Doctor previously visited an amusement park "controlled" by aliens. (TV: The Greatest Show in the Galaxy)
 * Clara's mobile phone has no service, indicating that the Doctor didn't give her a superphone, as he had with every one of his regular companions since his ninth incarnation. (TV: The End of the World, 42, The Doctor's Daughter, Dinosaurs on a Spaceship) It is strongly implied that Angie is given one at the end, however.
 * The Doctor says to the Cybermite, 'Not even a cybermat'. (TV: The Tomb of the Cybermen)
 * The Doctor echoes a quote from his former companion Rory Williams when confronted by the troops aiming guns at him: "Don't shoot, I'm nice!" (TV: The God Complex)
 * The Doctor's defeat of the Cyber-Planner, distracting him with a bluff about an alleged checkmate to drain his power, is the same stratagem he used against Fenric in his seventh incarnation. (TV: The Curse of Fenric)
 * The Doctor refers to an enemy as "beautiful." (TV: Tooth and Claw, The God Complex)
 * Webley claims that the Chess playing Cyberman is the 699th Wonder of the Universe. (TV: Death to the Daleks)
 * UNIT also designed a device that would blow up a planet to be used if left with no other options, the Osterhagen Project. (TV: The Stolen Earth/Journey's End)
 * The Doctor and Mr. Clever discuss the Doctor removing himself from databanks across the universe. (TV: Asylum of the Daleks, Dinosaurs on a Spaceship, The Angels Take Manhattan)
 * Porridge's Empire is probably the New Roman Empire mentioned in The End of the World, given the use of Roman titles and imagery.
 * The Doctor uses the phrase "You've had some cowboys in here" (TV: The Girl in the Fireplace, ''The Eleventh Hour).

Home video releases
to be added