Call Back / Doctor Who

• "Father's Day": While he's angry with Rose for saving her father and thus changing the past, the Doctor says that he's "picked another stupid ape", in reference to Adam Mitchell, who was kicked off the TARDIS in the previous episode for attempting to use time travel to enrich himself.
• "The Empty Child"/"The Doctor Dances":
  • It remains to be seen whether the Time Agents referenced by 51st century Captain Jack Harkness in the new series are a Call Back to the Time Agents mentioned by his contemporary Magnus Greel in the Fourth Doctor serial "The Talons of Weng-Chiang".
  • Although the above-mentioned Adam Mitchell is never directly referenced, the Doctor is not fond of Jack at first, asking Rose where she picked him up. And this is before he realizes Jack's full, if unwitting, involvement in the plot.
• "Bad Wolf":
  • The Doctor mentions having gone to Raxacoricofallapatorius, following on from "Boom Town".
  • The answer to one of the questions on The Weakest Link is "The Face of Boe". Rose gets it right because she's met him before.
• "The Parting of the Ways": Like in "Genesis of the Daleks", the Doctor has the power to destroy the Daleks, but goes through a moral dilemma, ultimately deciding not to go through with it.
• "The Christmas Invasion":
  • After stumbling out of the TARDIS at the beginning, the Doctor passes out on the ground in a position identical to those taken by many classic series Doctors before and after their regenerations.
  • Harriet Jones, Prime Minister^* Yes, we know who she is makes a point of learning the names of everyone she meets. Given that the last time she appeared, she never learned the name of a government aide (Indra Ganesh) who was killed by Blon Slitheen, it's likely to make sure that she knows this time.
• "School Reunion" was one big Call-Back to the Fourth Doctor's era. As well, there was a more short-term Call Back: The Doctor explains that he can't open the Krilitane device because it's got a "deadlock seal". The same thing prevented him from unlocking the door from the Big Brother house in "Bad Wolf".
  • Deadlock seals have been mentioned repeatedly since, to the point where it's stopped being a Call-Back to earlier references and started being a standard part of the series.
• "The Girl in the Fireplace" has an automaton going Broken Record until our heroes figure out the obvious, just like K9 in the very previous episode.
• "Rise of the Cybermen": For the first half of the episode, the Doctor wants nothing more than to escape from the Alternate Universe. The last time he was in an alternate universe, it... didn't end well.
• "The Impossible Planet"/"The Satan Pit": The Ood look like a cross between the Sensorites and the Monoids. "Planet of the Ood" would later reveal they're even from the same solar system as the Sensorites.
• "Army of Ghosts":
  • The Cybermen hiding in Torchwood reveal themselves in a homage shot to the way the Mondasian Cybermen clawed out of their pods in "The Tomb of the Cybermen".
  • The Doctor's warning about aliens needing to stay away because the humans are coming has come true, as Torchwood sees it as perfectly within their rights to shoot down any aliens that enter their airspace whether they're hostile or not.
• "Doomsday": The Doctor tries to send Rose away for her own safety. She's not having it, proclaiming "He's not doing that to me again!"
• "Smith and Jones": Martha's "welcome aboard" scene is almost identical to Peri's from "Planet of Fire". In both cases, the Doctor and companion fall on the console before the Doctor makes his welcome.
• "Daleks in Manhattan"/"Evolution of the Daleks" isn't the first time we've seen Daleks in the Empire State Building.
• "The Lazarus Experiment":
  • The Doctor's description of the Lazarus monster as an "evolutionary reject" is notably similar to the way the Fourth Doctor described the life-eating Fendahl in "Image of the Fendahl", creating very dark implications for old-school fans about the way things might have developed if it hadn't been killed quickly.
  • There's a hilarious Shout-Out to the Third Doctor's technobabble of choice, where the Tenth Doctor complains that it took him longer than usual to "Reverse the Polarity".
• "Utopia":
  • The Doctor talks about how humans are "indomitable".
  • The Chameleon Arch returns. It turns out the Doctor's not the only Time Lord to use one this series...
• "The Sound of Drums":
  • The Master did the four-beat drumbeat with his fingers once before, though it didn't mean anything until this episode.
  • Saxon was the Minister of Defence who ordered the destruction of the Racnoss.
• "The Fires of Pompeii":
  • The Doctor mentions that he had nothing to do with Rome burning. "...Okay, maybe a little bit."
  • The Doctor's mention of "Volcano Day" nods to a comment made by Jack Harkness in "The Empty Child", where he suggested the destruction of Pompeii as a good event for time travellers running "self-cleaning" cons to use.
• "Planet of the Ood":
  • The Doctor is all gleeful to walk into a snowstorm of actual snow, after several false starts.
  • The Oodsphere is in the same system as Sensphere, home of the Sensorites. The Doctor even notes his visit to the Sensphere was "ages" ago.
  • The 42^nd century is the time of the Second Great and Bountiful Human Empire, which, unlike the Fourth, actually exists. Presumably this would be the same "empire" Mr. Jefferson mentioned back in "The Impossible Planet".
  • Donna wonders whether humans spreading out so far is a good thing — does it make them explorers or a virus? The Doctor responds that sometimes he wonders; he had a similar conversation with Leela in "The Invisible Enemy".
  • The Friends of the Ood were mentioned by the crew of Sanctuary Base 6 back in "The Impossible Planet".
• "The Poison Sky": When the Doctor is given a gas mask, he puts it on and asks, "Are you my mummy?"
• "Silence in the Library"/"Forest of the Dead": As confirmed by Word of God, the squareness gun River Song owns in this story is the same one used by Captain Jack Harkness in "The Empty Child"/"The Doctor Dances". River took it in the Doctor's future after Jack left it in the TARDIS at the end of Series 1.
• "Turn Left":
  • Just like the Doctor a few episodes before, Rose dislikes being saluted while working with an alternate-timeline UNIT.
  • At the end, Rose's appearance and the upcoming danger is heralded by the words "Bad Wolf" appearing everywhere the Doctor looks. These were the Arc Words of Series 1, appearing everywhere they went, but not nearly as frequently.
• "The Stolen Earth":
  • A great many of the stolen planets: Clom, twin planet of Raxacoricofallapatorius and home of the Abzorbaloff; Woman Wept, visited by Rose and the Ninth Doctor; the Lost Moon of Poosh, subject of Dee Dee Blasco's research paper; Pyrovilia, lost home of the Pyroviles; and the previously-unnamed Adipose 3, which Miss Foster didn't know was literally missing.
  • Remember how in "Genesis of the Daleks", Kaled General Ravon's medical scanner didn't know what to make of Harry? When Davros opens his shirt, we see why.
• "Journey's End":
  • During a small-scale test, the Reality Bomb annihilates humans with the same effect used when Bad Wolf annihilated the Daleks.
  • Sarah Jane and Rose remember each other from "School Reunion".
• "Planet of the Dead":
  • Captain Erisa Magambo, the commander of the UNIT forces present, was last seen in the alternate universe of "Turn Left".
  • The Doctor reminisces when Christina calls him "Spaceman":
    "I had this friend, once. She called me 'Spaceman'."
  • Carmen's prophecy that the Doctor's song will be ending soon echoes the words of the Ood in "Planet of the Ood".
• "The Waters of Mars":
  • Fixed points in time return from "The Fires of Pompeii". Just like back then, the Doctor uses the TARDIS to save a few people at the last minute, although here it isn't a good thing. He also rehashes the argument he had with Donna in the earlier episode, then talks about everything he does to make that happen, when trying to persuade Adelaide to let him leave.
  • The Doctor is wearing the spacesuit he got from Sanctuary Base 6.
  • When the shuttle explodes, several of the Doctor's lines about the Time Lords and his status as the Last of His Kind are echoed as he stares at the wreckage.
• "The End of Time":
  • The Big Bad is Rassilon, founder of Time Lord society, resurrected to serve as Lord President.
  • The Master's drumbeat is explained as a real signal sent by the aforementioned Big Bad, in what turns out to be a Stable Time Loop.
  • In the denouement, the Doctor goes and visits every single companion he'd had in the new series up to that point, as well as supporting characters like Jackie Tyler and Luke Smith. Even Alonso makes an appearance!
• "Victory of the Daleks":
  • The concept of Daleks pretending to be servants goes all the way back to the Second Doctor serial "The Power of the Daleks". Back then, the Daleks said "I am your ser-vant!", here they say "I am your sol-dier!" That same serial also introduced the Progenitor, as one had crash-landed on Vulcan. This episode clarifies its intended purpose.
  • The Doctor declares that this encounter will be the "final end" for the Daleks.
  • The Doctor asks Amy to tell Winston Churchill about when the Daleks "invaded [her] world", and is extremely disturbed when she has no idea what he's on about.
  • This is not the first time the Doctor has all but dared a Dalek to kill him.
• "The Time of Angels":
  • The crash of the Byzantium was one of the future events River alluded to in passing in "Silence in the Library".
  • River's message to the Doctor contains the letters "Theta Sigma" (ΘΣ), his old Academy nickname.
  • The Angels communicate by stealing the voices of their victims, just like the Vashta Nerada.
• "Flesh and Stone": Angel Bob says "The Doctor in the TARDIS" and River mentions the Pandorica, both previously done by Prisoner Zero. As well, the Atraxi eye appears on a screen briefly.
• "Vincent and the Doctor": Amy tells Vincent he should consider trimming his beard before he next kisses someone. Later, when Vincent is overwhelmed by Dr. Black's praise, he gives him a kiss on both cheeks. As he pulls away, Vincent mutters "Sorry about the beard."
• "The Lodger": The Doctor greets Craig and several of his friends with air-kisses to both cheeks, having seen Vincent greet people that way in the previous episode and assuming it might be the way people greet each other in the early 21^st century.
• "The Pandorica Opens": The titular painting with the coordinates for the Doctor is created by Vincent van Gogh, and Churchill, Bracewell and Liz Ten help deliver it.
• "The Doctor's Wife": The little boxes found by the Eleventh Doctor first made their appearance when the Second Doctor used one at the end of "The War Games".
• "The Day of the Doctor": In the end, the reason the War Doctor decides he must end the Time War is, fundamentally, the very reason that the Fourth Doctor refused to push the button and destroy the Daleks at their genesis: a great evil done which inspires great hope and justice. Incidentally, Russell T Davies has described the events of that episode as the "opening salvo" of the Time War.
  • Also, what the War Doctor planned to do was almost exactly the same as Davros did in the same episode, for the same reason (though Davros was probably lying): to destroy both his own and the enemy's races for the sake of peace.
• "The Woman Who Fell to Earth":
  • The Doctor survives a fall from at least aircraft altitudes without a scratch.
  • The episode begins with the same general situation as "The Eleventh Hour": the freshly-regenerated Doctor, as a direct result of damage to the TARDIS caused by said regeneration, falling out of the sky and landing in an English municipality at night. Only, unlike Eleven, Thirteen doesn't have the TARDIS to cushion the fall.
  • Also like "The Eleventh Hour", the Doctor doesn't initially have either a sonic screwdriver or access to the TARDIS.
  • After jumping between two cranes, the Doctor hangs on for dear life in a fashion reminiscent of Four in "Logopolis". Unlike him, though, she doesn't fall.
  • At the end, the Doctor builds a teleporter to take her to the location of the TARDIS by locking on to the ship's unique energy signature, created by its unique power source.
• "The Ghost Monument":
  • The TARDIS became the titular Ghost Monument by being caught in a materialization loop, similar to what happened in "The Lodger".
  • The Doctor breaks out Three's favoured Venusian Aikido to subdue Epzo when he's holding Angstrom at gunpoint.
  • The Doctor persuading the TARDIS to open up as she's lost her key is similar to Twelve claiming that all doors are slightly psychic and then using telepathy to open one.
  • "You've redecorated." Only this time, the redecoration is approved of.
  • The TARDIS' new console biscuit dispenser may reference both Eleven's love of Jammy Dodgers, and Twelve's mention of a macaroon dispenser while giving Bill directions to the toilet.
• "Rosa":
  • Krasko, the villain, is a former inmate of the Stormcage Containment Facility.
  • The Doctor once again refers to a vortex manipulator as "cheap and nasty time travel".
• "Arachnids in the UK":
  • After meeting the Doctor, Najia Khan expresses concern for her daughter Yaz, asking her how she knows her and who she is, echoing Jackie Tyler and Francine Jones.
  • Ryan gets a letter from his deadbeat dad apologizing for being absent after Grace's death.
• "The Tsuranga Conundrum" has an automated vehicle that is attacked by a dangerous creature after its autopilot steers it onto a route it's never taken before.
• "Kerblam!" begins with the Doctor receiving a delivery from the titular retailer... a very overdue delivery, as it's a fez ordered two incarnations back.
• "It Takes You Away":
  • "Warriors' Gate" also contains mirror portals in a collapsing, labyrinthine Void Between the Worlds, though in this case the White Void Room is on the other side of one of the portals, rather than being the void itself.
  • In "The Rings of Akhaten", the climax has the Eleventh Doctor offer his memories to the parasite planet in the hopes of appeasing it, since no one else around has as many memories as he does. Here, Thirteen offers to stay with the Solitract since having just her, with all of her experiences, around will give it much more to work with than just Erik (which helps him realize that his "wife" is just an illusion). In both cases, the Doctor's solution doesn't work out, but there's an alternative — Eleven's memories can't compare to the infinite memories-that-never-were offered by Clara's leaf, and Thirteen can't stay after all because both universes will collapse, but she can promise to remember it as a friend and vice versa, which it accepts as enough.
  • As in "Last Christmas", a companion of the Doctor is tempted to stay in a false reality where a deceased loved one is still alive. The main difference is that the Solitract doesn't mean to harm Graham, whereas the Dream Crab was slowly killing Clara.
• "Resolution": When the Dalek controlling Lin researches Earth's defences and what it's up against, the Black Archive is referenced on the laptop screen. The Archive was last seen in "The Zygon Inversion". It's hinted that the Dalek material that the controlled Lin steals from MDZ may have come from there.
• "Spyfall":
  • This is not the first time someone's tried to kill the Doctor by remote-controlling the satnav of a vehicle they're in and making it drive somewhere perilous.
  • The Doctor describes her Gender Bender as "I've had an upgrade." Missy referred to the same thing as "Some of us can afford the upgrade!"
  • The Doctor's tuxedo coat sports a red inner lining like some of Twelve's coats. The double-breasted style calls to mind the green greatcoat that Eleven wore a few times in Series 6.
  • This is not the first time a seemingly ordinary building in a desert-like region has turned out to be a TARDIS in disguise.
  • The Master likes it when the Doctor says his name.
  • The Doctor disapproves of a character's willingness to use weaponry, but not so much to let it be used to save the day. We also get vague hints that the Doctor is more than they seem.
  • Graham, Ryan and Yaz's situation in part 2 when they're framed for a crime and forced to go on the run is very reminiscent of the Tenth Doctor, Martha and Captain Jack's situation in "The Sound of Drums", complete with the female companion's phone calls home being traced. That was also a story involving the Master.
  • The Master once used the drumbeat in his head to get the Doctor's attention. Here, the Doctor flips it to get his attention.
  • The Doctor initiates a telepathic conference between herself and another Time Lord, saying "Contact", a technique not seen since "The Three Doctors". She even refers to it as "classic".
  • The artron energy that time travellers soak up from the Time Vortex comes up again: the Doctor and Yaz wound up in the Kasaavin's home dimension instead of dead because the entities were confused by it.
  • The Thirteenth Doctor yet again gets grabbed in a chokehold by a male villain she's just intentionally angered, but is unbothered because the situation is actually going her way.
  • The Doctor shows up with two historical guest stars, and the companions fear that they're being replaced.
  • The Doctor being reminded to go back in time to rig Barton's airplane to save her companions' lives is reminiscent of Eleven's time-hopping in an almost-destroyed universe.
  • Ada's protests about getting her memory wiped are reminiscent of those of Donna Noble.
  • At the end, the Master mentions an Awful Truth involving the Timeless Child as the reason for certain relatively recent actions of his.
• "Orphan 55":
  • Yet again, the Doctor and company are forced to flee from hostile creatures on the surface of a Death World by heading into an underground tunnel.
  • A possible future in which Earth is wrecked was previously seen in "Pyramids of Mars".
• "Nikola Tesla's Night of Terror":
  • The Silurian blaster used by one of the Skithra is extremely similar to those used by the Silurians in previous new series appearances.
  • The Skithra Queen asks the Doctor if she's ever seen a dead planet. The Doctor's actually seen that twice already this season.
• "Fugitive of the Judoon":
  • Graham is once again mistaken for the Doctor.
  • Ruth, as the Doctor, used a Chameleon Arch to hide her identity. Like the Yana Master, she's been undercover for years and heard voices.
  • An unusual gravestone alerts the Doctor that the seeming "grave" isn't. And both graves are connected to the TARDIS.
  • Thirteen shows Gat a vision of the ruined Citadel to prove that she isn't lying about Gallifrey's destruction in her time.
  • Ryan calls Jack "cheesy" a couple of times, calling back to how Mickey would use it first to insult and then affectionately tease Jack.
• "Praxeus":
  • The fam uses com-dots to stay in touch while spread out across the Earth.
  • Much like Clara, Yaz has a go at being the Doctor. Thirteen sounds both impressed and annoyed at Yaz putting herself in danger.
  • Similar to the Autons, Praxeus is drawn to Earth due to heavy amounts of plastic pollution. The Doctor even suggests that the Autons might be behind the plot, but rejects the idea as they don't work like a virus.
  • The Doctor materializes the TARDIS around a ship about to explode, saving the occupant.
• "Can You Hear Me?":
  • When Sonya asks where she's been, Yaz replies Madagascar, Hong Kong and Gloucester. Incidentally, Yaz's dad has heard about what happened in Gloucester and, once again, chalked it up to a conspiracy.
  • This is not the first time the Doctor's encountered an alien being formerly worshipped as a god who was sealed inside a space prison after the natives got wise.
  • Ryan's nightmare involves a burning Earth and the Dregs from "Orphan 55".
  • Graham's nightmare deals with his fear of his cancer returning and how he met Grace because she was his nurse, both details mentioned in his first episode.
  • The Doctor's brief nightmare is of the "Timeless Child" vision from "Spyfall".
  • Graham confides his worries to the Doctor and she's not sure how to comfort him, mentioning that she's still socially awkward.
• "The Power of The Doctor": How does the Doctor realized he actually regenerated to a previous form? He knew his teeth.