The Day of the Doctor (TV story)

 was the fiftieth anniversary special of Doctor Who, the first full-length multi-Doctor story of the BBC Wales era, the first Doctor Who adventure shot in stereoscopic 3D, and the first adventure to be broadly available in cinemas in a number of different countries.

Moreover, it was shown at literally the same time round the globe on 23 and 24 November 2013 on television, prompting the Guinness Book of World Records to certify it as the largest ever simulcast of a television drama. In all, it was viewable in some 94 countries and 1,500 theatres worldwide. Domestically, the British Broadcasting Corporation's 2013/14 Annual Report cited it as the most watched drama on the BBC in 2013, with 12.8 million television viewers, and an additional 3.2 million iPlayer requests. It also broke or neared viewing records in a number of other regions around the world. Because of its theatrical run and subsequently strong home media sales, it is the single adventure with the highest gross worldwide sales in the history of Doctor Who. The success of this release led to the Series 8 premiere, Deep Breath, receiving a similar theatrical simulcast as it aired on television on 23 August the following year.

Amongst fans, the story was exceedingly popular. In a 2014 poll by Doctor Who Magazine which ranked all of the Doctor Who television stories aired to date, The Day of the Doctor ranked as "DWM readers' favourite adventure of the first 50 years". (DWM 474)

The episode featured the return of David Tennant as the Tenth Doctor and the appearance of John Hurt as a previously unknown incarnation of the Doctor: the War Doctor, in what was the final chronological adventure for his portrayal of the Doctor. His only full-length adventure on screen introduced a new iteration of the sonic screwdriver and a unique TARDIS control room predating those seen in Series 1.

Furthermore, the War Doctor's regeneration was shown, into what appeared to be the Ninth Doctor, completing a missing link in the chain of incarnations that started when Christopher Eccleston debuted in the 2005 relaunch of the series, Rose. The process of resolving the regenerations issue was being enforced by executive producer Steven Moffat, as he wished to have a "complete set" in time for Matt Smith's upcoming final episode.

Moffat also chose to requisition actor Paul McGann for one more outing as the Eighth Doctor in a mini-episode production, The Night of the Doctor one week after production wrapped on the anniversary special, resulting in a second former Doctor returning to the screen as part of the festivities. McGann filmed his own regeneration into Hurt's version of the Doctor, cementing the lineage of all Doctors up to Smith's incarnation onward.

The Day of the Doctor saw the return of the Zygons, last seen in the 1975 Fourth Doctor serial Terror of the Zygons, 38 years after their initial debut.

The Day of the Doctor provided a chance to reveal a missing element of the Last Great Time War that dramatically altered the outcome as viewers were previously led to believe. Instead of allowing Gallifrey to be destroyed, the Doctors were able to save it, giving the current incarnation a chance to forever shed his guilt from the outcome and begin a new mission to find his way home. The unique circumstances of this revelation also upheld the previous narratives set during the Russell T Davies era where the Doctor believed Gallifrey and its residents had been lost in battle.

Synopsis
The Doctors embark on their greatest adventure in this 50th anniversary special. In the 21st century, something terrible is awakening in London's National Gallery; in 1562, a murderous plot is afoot in Elizabethan England; and somewhere in space an ancient battle reaches its devastating conclusion. All of reality is at stake as the Doctor's own dangerous past comes back to haunt him.

Plot
A police constable walks the beat by the Coal Hill School and passes by a sign advertising "I.M. Foreman, Scrap Merchant". Inside the school, Clara Oswald is giving a lesson on. She ends on a quote by Marcus Aurelius: "Waste no more time arguing about what a good man should be. Be one."

The school bell rings. As her students leave, a teacher runs into the classroom informing Clara that her "doctor" called, and left an address. She grabs her helmet and hops on her motorbike. Exiting Shoreditch, Clara drives past a clock reading 5:16 p.m. and through a freeway tunnel. She reaches an open patch of road surrounded by grassland, where a lone police box is waiting for her.

Finally spotting the TARDIS, she drives straight through its open doors, closing them with a click of the fingers. The Doctor, perusing a copy of Advanced Quantum Mechanics, welcomes Clara back with a huge hug. Unexpectedly, the TARDIS takes off without starting the engines. Startled, the Doctor looks out to see a helicopter carrying the TARDIS away from the field; it's UNIT. He calls their head of Scientific Research, Kate Lethbridge-Stewart, from the phone on the TARDIS exterior.

UNIT scientist Osgood rushes to Kate with her personal phone as she is eating and observing their ravens of death, which need a change of batteries from Malcolm. Kate reminds Osgood to use her inhaler at the sound of her heavy panting before accepting the call.

The Doctor learns that he has been summoned to the Tower of London. Kate is surprised to learn that he is on-board the TARDIS, which they thought was empty and were moving for convenience. She has it and him brought directly to the "scene of the crime". Upon arrival, he is handed sealed orders from Queen Elizabeth I and taken into the National Gallery for proof of her credentials.

As they walk, the Doctor explains his relationship with UNIT to Clara, who is sceptical of the Doctor ever having had an actual job. They stop in front of an impossible painting, something that belongs "not in this time or place": an oil painting in 3-D. It depicts the fall of the Gallifreyan city of Arcadia on the last day of the Time War. Kate tells the Doctor that there is some controversy over the work's name. It is either named No More or Gallifrey Falls. The painting is a slice of frozen time, a form of Time Lord art.

The Doctor is visibly disturbed by the painting. As his old memories awaken, he shares with Clara his darkest secret: the life he has tried to bury for years. There was a past incarnation of the Doctor that fought in the Time War, and made the ultimate decision to eliminate the Daleks and the Time Lords. And it was done on the very day this painting depicts...

As the Daleks ravage Arcadia, the Gallifreyans are running in fear. There is little hope of survival. As children cry and the people scream, a soldier messages the High Council of Time Lords: Arcadia has fallen. He looks around and sees the Doctor's TARDIS. Then the elderly voice of the "War Doctor" asks the soldier for his gun. The Doctor carves a message for both warring civilisations to see into a nearby wall: NO MORE. As Daleks prepare to exterminate Gallifreyan refugees, the Doctor's presence draws their attention away from the innocent people and leads them to the wall with the message. Suddenly, the Doctor's TARDIS crashes through the wall, demolishing several Daleks. The Doctor's escape from Arcadia is witnessed by one surviving Dalek of the attack, though it is bisected. It questions the meaning of "NO MORE", bellowing "Explain! Explain!" The nearby Gallifreyan soldier shoots the Dalek with his gun, and the slain Dalek erupts in flames.

The High Commanders gather in the War Room, planning their next moves, with the General dismissing the High Council's upcoming plans as "they have already failed". They receive the Doctor's message, and the General is not pleased to learn of his presence, calling him a madman. A Time Lady rushes in to inform the War Council that there has been a breach in the Omega Arsenal in the Time Vaults.

The most feared and forbidden weapon in the universe is missing: The Moment. The Doctor has stolen it, and intends to use it to end the Time War once and for all. The Time Lords have already used all of the previously forbidden weapons, but dared not unleash this weapon in particular. It was said that the Moment was so advanced as to have developed a conscience, and could stand in judgement of the user. The General muses that only the Doctor would be mad enough to use such a weapon.

Footsteps can be seen leading away from the battle-scuffed frame of the TARDIS, which has been uncharacteristically abandoned by the Doctor. The sound of his voice issuing an ominous final warning is heard: "Time Lords of Gallifrey, Daleks of Skaro, I serve notice on you all. Too long I have stayed my hand. No more. Today you leave me no choice. Today, this war will end. No more. No more..." The Doctor's tired face comes into view as he strides across a desolate desert, a burlap sack over his shoulder.

He eventually enters a barn-like dwelling, where he uncovers a complicated mechanical box, covered in gears. The device ticks loudly as its clockwork-like parts rattle and clank. As the Doctor studies it, he cannot find a discernible trigger mechanism. While he puzzles over how to activate it — grumbling "Why is there never a big red button?" — he hears a rustling sound. He opens the door and calls out. A girl's voice behind him reassures him that it’s "just a Wolf".

Startled, he turns around to see what appears to be Rose Tyler. He doesn't recognise her, as this point in his timeline predates his first meeting with Rose. He grabs her arm and throws her out the door, only for her to appear inside the barn again, sitting on the Moment. She begins questioning the Doctor as to his motives and rationalisations (though it looks like she is making fun of him). The Moment also asks if the Doctor parked his TARDIS far away from the dwelling so that it would not witness what he was about to do. Not realising what she is, he orders her out, and then burns his hand on the box. Impishly, she guides the Doctor to realise that she is the interface of the Moment. She can hear the Doctor's thoughts, and has attempted to assume the form of a familiar figure from his past; however, the Moment has a history of confusing the past with the future, and so has chosen the form of Rose Tyler as the Bad Wolf to be its manifestation.

War-weary and bitter, the elderly Time Lord tells her to stop calling him "the Doctor", claiming he has lost the right to bear the title. She replies that he will be the one to save the universe. He explains that the suffering of the universe is too great, and he must end it. He also intends to meet his death after using the Moment, not wishing to live through the bloodshed, but she decides that his fate and punishment will be to survive the activation and face the consequences. Like a conscience, she challenges his words and actions, guiding him towards his future. He will destroy the Daleks, but he will also murder his own people, asking him how many children on Gallifrey will die, but he has no idea. After suggesting that one day, he will find a way to count them, the Moment opens a window in time, to show him the man he will become. A time fissure opens - and a fez falls out, much to the mutual confusion of the Doctor and the Moment...

Back in the 21st century, Kate explains that Queen Elizabeth left the painting to prove that the orders do come from her. The Doctor breaks the seal and reads her words: "My dearest love: I hope the painting known as Gallifrey Falls will serve as proof that it is your Elizabeth that writes to you now. You will recall that you pledged yourself to the safety of my kingdom. In that capacity, I have appointed you Curator of the Under-Gallery, where deadly danger to England is locked away. Should any disturbance occur within its walls, it is my wish that you should be summoned. Godspeed, gentle husband."

As Kate leads the Doctor and Clara away, a nearby UNIT scientist named McGillop receives a mysterious phone call. Befuddled, he stares at the painting, wondering why he should move it.

The Doctor and Clara approach another painting, which shows the figure of Queen Elizabeth the First, and the Doctor. Clara sees this is proof the Doctor once knew her. However, it is the past incarnation of the Doctor, and from the Eleventh Doctor's vantage point, that portrait was done a long time ago, long enough that he was a different man back then...

In England in 1562, the Tenth Doctor and Queen Elizabeth I ride out of the TARDIS on horseback, the Doctor having proven that it really is bigger on the inside. They share a picnic on a hill, after which he proposes marriage. When she joyfully accepts, the Doctor accuses her of being a Zygon shapeshifter that has replaced the real Elizabeth. He whips out a "device that goes ding" to prove that she is a shapeshifter, before realising that it was the horse they were riding. They run for their lives, the Doctor now an engaged man. They split up in the woods, but Elizabeth is accosted by the Zygon. The Doctor runs through the woods, even threatening a rabbit before he is reunited with Elizabeth. However, a doppelganger of her appears, and he is unable to tell who is who. Suddenly another time fissure appears, and a fez falls through, shocking the Doctor and company.

Back in the National Gallery, Kate welcomes the Eleventh Doctor and Clara to the Under-Gallery, established by Elizabeth I to house dangerous art. The Doctor notices that the floor is covered in stone dust, and asks a scientist named Osgood to analyse it (with a triplicate report and lots of graphs). As they walk through the gallery, the Doctor spots a fez in a glass case and immediately dons it, much to the bemusement of Clara, who wonders if he can ever go past one without putting it on (answer: no).

Kate shows them more 3-D paintings, all landscapes, with the broken glass from their shattered frames covering the floor. The Doctor notes that the glass has been shattered from the inside, and Kate says that they all contained figures which are now missing. Suddenly, another time fissure opens. Annoyed, the Doctor faintly recalls seeing the fissure before, before realising that the fez that had fallen through in 1562 was the fez he was now wearing. Delighted, he throws the fez into the fissure and follows it. Clara tries to follow, but Kate restrains her.

The Eleventh Doctor falls through the fissure and lands in front of the Tenth in the sixteenth century. Stunned, the Tenth Doctor dons the fez himself. The Eleventh pops up and gabbles excitedly about how skinny his predecessor is, which makes the Tenth realise who he is. They incredulously pull out their sonic screwdrivers and compare them. As they begin bickering, the time fissure increases in intensity. The Doctor orders the two Queens to run away; both kiss the Tenth Doctor and flee. After pointing out that one of the women his counterpart just kissed was definitely a Zygon, the Eleventh shouts through the funnel to Clara. Hypothesising that the fissure can go both ways, he tosses his fez in, but it fails to appear in Clara's time. Kate then leaves, to call one of the UNIT members to bring her the Cromer file - not noticing a dark shadow behind her...

At the end of the Time War, the War Doctor picks up the fez and steps into the fissure. Back in 1562, the two Doctors try to reverse the polarity, but the use of two sonic screwdrivers at once confuses the polarity, resulting in the War Doctor falling through, landing in front of his future selves. He jovially greets them, asking after the Doctor and mistaking them for companions-to-be. The two older Doctors — both horrified to see him — simply pull out their sonic screwdrivers, affirming their identity to their younger self. Completely unimpressed by his future incarnations, the War Doctor asks if he is going through a mid-life crisis.

Suddenly, they are surrounded by the Queen's soldiers. They are threatened by them, but Clara's voice sounds from the fissure, allowing the Doctors to convince them that she is "The Wicked Witch of the Well". Kate has, at that point, returned to Clara. The Queen returns to the group, implying that her human counterpart is dead. She has the trio of Doctors arrested and taken to the Tower of London (with the Eleventh loudly hinting for her to take them there). The hint is picked up on by Kate, who takes Clara to the Black Archive to retrieve Jack Harkness' vortex manipulator.

The Doctors are thrown in a cell with a wooden door. The War Doctor tries to sonic the door, but it fails. The Tenth asks why these three Doctors have been brought together.

In the present, Osgood and McGilop are reading the results of the analysis of the stone dust. The dust is from materials not found in the structure of the building, but common in statues. Osgood realises that the statues must have been smashed, and suddenly understands why: the inhabitants of the paintings needed a hiding place. The Zygons reveal themselves from underneath the dust cloths covering what the humans had believed were statues. The aliens accost McGilop, and corner Osgood. Osgood prays for the Doctor to save her, but instead of being killed, she is faced with her duplicate. The Zygon taunts Osgood, but she gains the upper hand by tripping the alien with her scarf, and runs.

Kate and Clara enter the Black Archive, housing the most dangerous alien tech recovered by UNIT. Its contents are so top secret that its staff has their memories modified every day. Apparently, this has happened to Clara at least once, as she has already obtained the necessary clearance to enter the archive. They view the Vortex Manipulator, by trying to find the activation code. The Doctor has the code, but he hasn't informed UNIT of it. A scientist phones Kate, and she orders him to send a picture of some numerals (the activation code) that the Eleventh Doctor carved into the wall of the cell in 1562 for them to find centuries later. Osgood and McGilop enter the Archive, to Clara's surprise. They and Kate reveal themselves as Zygons. As they prepare to replace Clara, she sees the picture of the numerals on the phone. Taking a desperate gamble, she enters the code into the Vortex Manipulator and travels to the past.

In the 1562 Tower of London, the Eleventh Doctor scratches the activation code onto a wall in their cell, while the other two Doctors puzzle out how to escape. The War Doctor proposes an isolated sonic shift in the door molecules in order to disintegrate the door, but the Tenth Doctor rejects the idea, saying it would take centuries to calculate the necessary formula. The War Doctor starts bickering with the Tenth and Eleventh Doctors, chastising them for their shame of being "grown-up". Subdued, they look at him darkly, reminding him of the day he ended the Time War (unaware that this Doctor is actively in the process of making that choice).

The Moment reappears, unseen and unheard by the other Doctors, and urges the War Doctor to ask his future selves the question that he needs to know: How many children died on Gallifrey that day. The Eleventh Doctor says, "I've absolutely no idea." The Tenth Doctor suddenly gives him a look of piercing outrage and disgust, because the same thing his future self is ignoring is a significant reminder of his personal duty to be a hero instead of a warrior so innocent people no longer have to die. However, the Eleventh Doctor has already taken that route and suffered great personal losses for trying to play hero. Somewhere along the line, he quit being heroic and the simple act of forgetfulness turned into a defence mechanism so the abundance of his regrets cannot torment him anymore.

After the Eleventh Doctor claims he doesn't know how many children died, he says he's forgotten the events of that day; he's so old that he's not even sure of his age anymore, so old that he can't remember if he's lying about his age. However, the Tenth Doctor angrily asks how the Eleventh could ever forget something as important as this particular number, and bitterly states that there were 2.47 billion children on the planet that day. Disturbed by his successor's impassive nature, he asks him, "For once, I would like to know where I'm going." Vexed by this remark, the Eleventh Doctor coldly replies, "No, you really wouldn't!" The Tenth Doctor looks back at him, eyes wide with fear. The Moment explains to the War Doctor that the Tenth Doctor has become "the man who regrets" and the Eleventh "the man who forgets". They are the future of the Doctor.

The Moment reminds the War Doctor that his sonic screwdriver, at the most basic level, is the exact same device as the ones used by his counterparts: "Same software — different case". He realises that if he scans the door and implants the calculations as a permanent subroutine in the screwdriver, it will take hundreds of years to work out the formula necessary to disintegrate the door, meaning that the Eleventh Doctor's screwdriver, being essentially the same as the ones before it, has the completed calculation ready to go. They exuberantly congratulate themselves on their cleverness before Clara pushes open the door — which has been unlocked the entire time. Clara chastises the three Doctors for being so obtuse, and the Queen comes in, telling them that she left the door unlocked as a test. She takes them down to the Zygons' lair to show them their plan.

Osgood walks in the halls of the Under-Gallery, before discovering the real Kate trapped in a Zygon nest. Kate's body template is being used to refresh the image of her Zygon doppelganger. Osgood frees her, but Kate bemoans the fact that the Zygons now have control of the Black Archive.

The Doctors and Clara follow the Queen to the lair, whereupon they discover that the Zygon homeworld was destroyed in the early days of the Time War, and so they have decided to take Earth as their new home. However, the sixteenth century version of Earth is too primitive to be comfortable to the invading shapeshfiters, so they intend to invade the cushier future in order to establish their new homeworld. They therefore have translated themselves into stasis cubes, which are the Time Lords' three-dimensional paintings. The Tenth Doctor berates the Zygon commander for doing a lousy job of replicating the real Queen Elizabeth, but she reveals (to his mortification) that she is the real Elizabeth: She slew her twin in the forest and took her place as Zygon commander. She calls on the Doctor to save England, but first whisks him away to be married (with his past and future selves as reluctant witnesses, and an enthusiastic Clara throwing confetti).

The three Doctors and Clara return to the Tenth's TARDIS (with the other two insulting the current desktop theme). The presence of three different Doctors causes the TARDIS to short a bit, showing the interior of the War Doctor's TARDIS, then finally the most current TARDIS desktop (which also receives an insult). They set off for the Black Archive.

Kate, Osgood, and McGillop confront their doppelgangers in the Black Archive. Kate threatens to detonate a nuclear warhead beneath the Tower, destroying all of London in order to protect the planet from the Zygons, and voice-activates it, blocking her Zygon duplicate's attempts to stop the countdown with her identical voice pattern. The Eleventh Doctor's voice crackles on via the space-time telegraph he had once given to her father, begging Kate not to detonate but she cuts him off. He tries to land, but the Tower of London had been made TARDIS-proof to prevent his interference. However, the War Doctor figures out a way to get in - the stasis cubes. The Doctor calls McGillop in the past, and instructs him to bring the "No More"/"Gallifrey Falls" painting to the Black Archive...

The two Kates fight over the detonation, both needing to agree in order to stop the detonation. The real Osgood begs the Doctor to save them again, as the Doctors and Clara force their way out of the painting, having frozen themselves in it earlier. The Doctors now face the Fall of Arcadia in real time as it unfolds, and are immediately met with an attacking Dalek, which they repel with their sonic screwdrivers. It crashes through the glass of the painting and the Doctors emerge. Clara soon follows.

The three Doctors hand the Kates an ultimatum when they refuse to disarm the Archive's nuclear option: They trigger the memory modifiers to confuse everybody as to whether they are Human or Zygon. Then, if they stop the detonation and create a peace treaty (which is sure to be incredibly fair, as the negotiators can't remember which side they're on), they will have their memories restored. Utterly confused over their identities, the two Kates stop the detonation in the nick of time and begin to negotiate the treaty.

As they hash it out, Clara speaks to the War Doctor. She has somehow figured out that he hasn't used the Moment yet, explaining that "her" Doctor always talked about the day he wiped out the Time Lords. She says that he would do anything to take it back, but the War Doctor remains convinced that his actions will save billions of lives in the future. Across the room, the War Doctor sees the form of the Bad Wolf once more. The Moment has come. He tells the interface he's ready, and Clara turns to find who he's talking to; when she turns back, he's vanished.

Returned to the barn on Gallifrey, the War Doctor stands in front of the Moment, which has simplified its interface by his request — the trigger mechanism is now a big red button for him to push. The interface questions him once more, trying to convince him of his goodness. He still doesn't believe he is worthy of the name "Doctor", losing all hope for himself and his people. The interface reminds him of his hope as his future selves step out of their TARDISes. They join him at the Moment, finally forgiving him, and themselves, for his actions, ready to support the man who was the Doctor more than anybody else. The three of them prepare to push the button together, but Clara tearfully objects. She knew that "the Doctor" had activated the Moment and destroyed his homeworld, but she had never imagined the Eleventh Doctor, her Doctor, with his hand on the button.

The reality of the Time War projects around them: children crying, innocents suffering. The Doctor could not find another way to end it all, but Clara believes in a different solution. She reminds the Time Lord of who he is: the Warrior, the Hero, and the Doctor. They've had plenty of warriors, and what he will do is a heroic act unto itself. What the universe needs now is a Doctor who lives up to the name he chose for himself: never cruel or cowardly, never giving up, never giving in. A new day dawns on Gallifrey: a day of hope.

At that, a brilliant new idea descends on the room; the Eleventh Doctor says that he's had a long time to think about it — he's changed his mind! The intent of the Moment worked: the War Doctor saw the future he needed to see. Picking up on his future self's idea without explanation, the War Doctor exclaims that he could just kiss "Bad Wolf girl" right now, which catches the Tenth's attention, only for him to be distracted from it as he realises what his counterparts were getting at and agrees that it's a wonderful idea. They have changed their minds about using the Moment, and the Eleventh Doctor disarms the device with his sonic screwdriver. Instead, they intend to freeze Gallifrey in a moment in time, slipped away in a pocket universe, the way the Zygons froze themselves into Time Lord art. When Gallifrey vanishes, the sphere of Dalek ships surrounding the planet and firing constantly will be exterminated in their own crossfire before they can cease firing, and the universe will believe that the two races destroyed each other.

On the last day of the Time War, another message from the Doctor appears before the High Command: GALLIFREY STANDS. The three Doctors race in their TARDISes towards Gallifrey, and transmit to the War Room. Three transmissions, each showing a different Doctor (much to the General's dismay), appear. They explain their mad plan to save Gallifrey. They will position themselves around the planet equidistantly, and freeze it through the stasis cubes. The General objects, claiming that the calculations would take centuries, but the Eleventh Doctor is well prepared for the task. After all, he's had centuries to think about it.

At that, the voice of the First Doctor is heard contacting the War Council. Ten more phone boxes fly around the planet, and all the past incarnations of the Doctor come together to save Gallifrey. His second through eighth incarnations check in with High Command, while the post-war Ninth Doctor delights in the act of redemption he always wished for, but will eventually be made to forget for two more incarnations. The General bemoans the idea that all twelve Doctors have arrived, when three was bad enough. However, his count is one short.

Androgar points out that all thirteen incarnations of the Doctor are present to save Gallifrey — a new incarnation from the Doctor's days yet to come is also on the way. A brief glimpse of this future Doctor shows a hand reaching for a lever in the Eleventh Doctor's console room, and a pair of fierce eyes watching the console monitor. As the Daleks increase their attack upon seeing the thirteen TARDISes, the General tells the Doctor to do it now. After a flash and a colossal explosion, the space becomes empty and quiet as one damaged Dalek fighter pod goes spinning off.

Back in the National Gallery, the Tenth, Eleventh, and War Doctors muse on the ambiguity of whether their plan succeeded. The presence of the mysterious painting of the fall of Arcadia remains an enigma to the three Doctors. The War Doctor bids a fond farewell to his replacements, who finally address him as "Doctor": a man fully worthy of the title, even if he will only know it briefly. Because the time lines are out of sync, the War Doctor and the Tenth Doctor won't be able to retain their memories of these events. They will forget them completely until they catch up to their Eleventh incarnation. However, right now, the War Doctor is content. He gives Clara a farewell kiss and takes a moment to sort out his TARDIS out from the other two in the gallery. As he pilots his TARDIS away, he suddenly sees his hands glowing with regeneration energy, and notices it makes sense, as his old body is "wearing a bit thin." After surviving the Time War, he is ultimately dying of old age. With his work done in the battle, the energy begins to overtake the War Doctor. He expresses one last desire that the change will leave him with "less conspicuous" ears this time. The War Doctor smiles peacefully as his next regeneration begins.

Acknowledging that he won't be able to remember the answer, the Tenth Doctor questions his successor as to "where they're going" that the Eleventh Doctor so clearly wants to forget. The Eleventh Doctor relents and reveals that they are destined to die on Trenzalore, in battle, with millions of lives lost. The Tenth Doctor says that's not how it's supposed to be, but the Eleventh Doctor tells him it is determined now. Preparing to leave, the Tenth Doctor tells himself that he's glad his future is in good hands. He kisses Clara's hand, and with a smile, starts to step into his TARDIS. Before he does, he expresses his desire to change their final destination of Trenzalore, saying: "I don't want to go." As the TARDIS dematerialises, the Eleventh Doctor remarks "he always says that".

Clara asks the Doctor if he would like to sit and look at the painting for a little while. He smiles, asking how she knew. Clara kisses him on the cheek and tells him that she always knows — it's his sad old eyes. As she steps into the TARDIS, she mentions that an old man, possibly the Gallery's curator, was looking for him.

The Doctor muses out loud that he would be a great curator. He could call himself "the Great Curator", retire and become the curator of this gallery. A very familiar voice affirms that he really might. The astonished Doctor looks over to see a very familiar face standing next to him. An old man who greatly resembles the Fourth Doctor speaks to him of the painting, which he says he acquired under "remarkable circumstances". He tells the Doctor that its two names are actually one: the true title of the painting is "Gallifrey Falls No More". The Doctor realises that he was successful, and Gallifrey was indeed saved. The mysterious man reveals that it is simply "lost", and that the Doctor has a lot to do. He also muses that he and the Doctor might be the same man from different perspectives, sounding wistful about days gone by, congratulating the Doctor on the new journey he is about to commence. As to whether or not he truly is an incarnation of the Doctor from the future, the Curator simply teases the thought, "Who knows, eh? Who... 'nose'?", and with a tap of his nose, he turns and walks away. The Eleventh Doctor concludes that he has a mission, the mission of a lifetime: he must find Gallifrey and return it and all its people to the universe.

Later, the Doctor speaks of his dreams, as he is seen to walk through the TARDIS console room. He says that he finally realises where he has been travelling all this time: home. He simply has taken the long way around. As he exits the TARDIS in the dream, the Doctor joins his eleven past selves in gazing up at the magnificent planet in the sky, determined to find Gallifrey and save his home once and for all.

Cameos
Actor Billie Piper also returned for the special in a different role, portraying the Moment, an ancient, sentient Gallifreyan device first mentioned in The End of Time, and taking the holographic form of the Doctor's former companion Rose Tyler as Bad Wolf.

The special also included the surprise debut of Peter Capaldi as the Twelfth Doctor, noteworthy for being an early cameo before officially assuming the role of the Doctor with Matt Smith's departure in the 2013 Christmas special The Time of the Doctor, as well as a cameo from an elderly Tom Baker, the former Fourth Doctor. Baker's character, the Curator, alluded to the Doctor "revisiting a few old faces" implying the Doctor will appear as he did in the past and resumes the Royal appointment bequeathed earlier in the story by Queen Elizabeth I.

Cast

 * The Doctor - Matt Smith
 * The Doctor - David Tennant
 * The Doctor - Christopher Eccleston
 * The Doctor - John Hurt
 * The Doctor - Paul McGann
 * The Doctor - Sylvester McCoy
 * The Doctor - Colin Baker
 * The Doctor - Peter Davison
 * The Doctor - Tom Baker
 * The Doctor - Jon Pertwee
 * The Doctor - Patrick Troughton
 * The Doctor - William Hartnell
 * Clara - Jenna Coleman
 * Rose - Billie Piper
 * Tom - Tristan Beint
 * Kate Stewart - Jemma Redgrave
 * Osgood - Ingrid Oliver
 * Time Lord soldier - Chris Finch
 * Androgar - Peter de Jersey
 * The General - Ken Bones
 * Arcadia father - Philip Buck
 * Time Lord - Sophie Morgan-Price
 * Elizabeth I - Joanna Page
 * Lord Bentham - Orlando James
 * McGillop - Jonjo O'Neill
 * Atkins - Tom Keller
 * Zygons - Aidan Cook, Paul Kasey
 * Voice of the Daleks & Zygons - Nicholas Briggs
 * Dalek 1 - Barnaby Edwards
 * Dalek 2 - Nicholas Pegg
 * Voice over artist - John Guilor

Uncredited cast

 * The Doctor - Peter Capaldi

Planets

 * The Zygon homeworld was destroyed during the first part of the Last Great Time War.

Technology

 * The Eleventh Doctor uses the TARDIS console's friction contrafibulator (TV: Vincent and the Doctor) to stabilise the control room desktop theme. (TV: Time Crash)
 * The number the Eleventh Doctor calls McGillop from is the same as Martha's old mobile — the one left on the TARDIS. This implies that the Doctor adopted this number as his main one.

Individuals

 * Jack Harkness's vortex manipulator was saved in the Black Archive of UNIT after one of his deaths. It later ended up in the possession of the Eleventh Doctor and Clara Oswald.
 * The board containing photos of Clara's last visit to the Black Archive also showcase photos of previous associates of the Doctor, including Wilfred Mott, Rory Williams, Amy Pond, River Song, Mickey Smith, Captain Jack Harkness, Kamelion, Leela, Sarah Jane Smith, K-9 Mark III, Harry Sullivan, Martha Jones, Peri Brown, Jamie McCrimmon, Romana II, Jo Grant, Alistair Gordon Lethbridge-Stewart, Nyssa, Craig Owens, Donna Noble, Captain Yates, Adric, Sara Kingdom, Tegan Jovanka, Barbara Wright, Polly Wright, Grace Holloway, Ben Jackson, Ian Chesterton, Susan, Lieutenant General Sanchez, Brigadier Winifred Bambera, Ace, UNIT Captain Erisa Magambo, and Rose Tyler.
 * Kate Lethbridge-Stewart's mobile phone has a TARDIS dematerialisation sound set as her ringtone when the Doctor calls.
 * Clara quotes Marcus Aurelius to her class.
 * A bust of Albert Einstein can be seen in front of the Cyberman painting in the Undergallery.

The Doctor

 * The Doctor's age is discussed by the three incarnations:
 * While confronting a rabbit which he briefly believes to be a Zygon in disguise, the Tenth Doctor says that he is 904 years old.
 * When asked how old he is by the War Doctor, the Eleventh Doctor says that he doesn't know and has lost track, settling on "Twelve hundred and something, I think, unless I'm lying." He goes on to say that he is so old he couldn't remember if he was lying about his age.
 * The War Doctor in turn says that he's 400 years younger than the Eleventh Doctor at this point, making him approximately 800 years old.
 * The incarnations of the Doctor previous to the Eleventh aren't able to retain their memories of their meetings nor the events lived together because their timelines are out of sync.
 * The Tenth Doctor will remember to have married Queen Elizabeth, however. (TV: The End of Time)

References to the real world

 * When Elizabeth explains how she killed her Zygon duplicate, she says, "I may have the body of a weak and feeble woman, but at the time, so did the Zygon." This is a direct reference to the, in which she was credited as saying, "I know I have the body of a weak, feeble woman; but I have the heart and stomach of a king, and a king of England too..."
 * The Eleventh Doctor calls the Tenth Doctor "Dick Van Dyke".

Ratings

 * UK: 12.8 million, 3.2 million iPlayer requests
 * World: 77 million

Specific to theatrical presentation

 * Two specially recorded scenes were shown before the special in its showing in cinemas. The first featured Dan Starkey as Commander Strax, accompanied by his Sontaran clone batch, lecturing the viewers on cinema etiquette. The second featured Matt Smith and David Tennant as the Eleventh and Tenth Doctors instructing viewers to put on their 3D glasses. The second ends with John Hurt's War Doctor suddenly appearing behind the two Doctors who turn towards him while he has his back to them as the feature starts.

Specific to the 3D version

 * The episode was shot, broadcast and screened in cinemas in stereoscopic 3D. Despite confessing that he was not a big fan of 3D movies, writer and show runner Steven Moffat came up with the idea of shooting the episode in 3D and despite his initial worries, found the 3D version to be "better" and "more satisfying" than the 2D version. Knowing that the vast majority of viewers would have watched it in 2D, director Nick Hurran made sure that his shooting style wasn't influenced "too much" by the episode's use of 3D. Nonetheless, Hurran meticulously researched the back-catalogue of 3D films in order to see what worked and what didn't. Steven Moffat believed that Hurran's research had led the director to view "every 3D film ever made". (DWM 468)
 * The original Doctor Who logo is not only in black and white; a 3D effect is added to suggest the logo moving towards the viewer.
 * The 3D paintings are obviously more 3D in the 3D version.
 * As the Eleventh Doctor walks out of the TARDIS onto the cloud bearing his other selves at the very end of the story, the effect is considerably "more 3D" than viewing the 2D version would suggest.

Common among all versions

 * The story is fronted by the version of the title sequence used on the original episode "An Unearthly Child", modified to include a BBC logo, and slightly shortened. (This version is slightly different than the opening used on the unaired pilot episode.) As such, this is the only episode to use a previously retired title sequence, rather than use the current one or introduce a new one.
 * The opening scenes further mimic the original open to An Unearthly Child: the first shot shows a police officer going by a sign for 76 Totter's Lane, and the second shot is set at Coal Hill School as class dismisses. Clara is now a teacher at Coal Hill School. A sign shows that I. Chesterton is chairman of the school's Board of Governors, also showing that a W. Coburn is headmaster — a likely in-joke reference to Anthony Coburn, who wrote An Unearthly Child, and Waris Hussein, Doctor Who's original director.
 * Day is the seventh televised multi-Doctor story. The others are: The Three Doctors, The Five Doctors, The Two Doctors, Dimensions in Time, Time Crash, and The Name of the Doctor.
 * The end credits list all the actors who have played the Doctor in the reverse order of their incarnations (with the exception of Peter Capaldi, who remained uncredited for his brief appearance). As a result, Matt Smith and David Tennant are listed first and second respectively, but Christopher Eccleston is credited above John Hurt.
 * Actor John Guilor is credited as 'Voice Over Artist' in the credits, although they do not say which role he voiced. Castingcallpro.com credits him as the voice of the First Doctor.
 * Radio Times credits David Tennant as 'The Tenth Doctor', John Hurt as 'The Other Doctor' and Billie Piper as 'Rose Tyler'.
 * Jonjo O'Neill (McGillop) is erroneously credited as 'McGuillop' in Radio Times.
 * The Radio Times programme listing was accompanied by a small colour head-and-shoulders shot of the Eleventh and Tenth Doctors in the wood, with the accompanying caption "Doctor Who / 7.50 p.m. / Matt Smith and David Tennant join forces in a tale celebrating 50 years of the show".
 * This is the first on-screen appearance of the Daleks not to feature those of the New Dalek Paradigm in the Steven Moffat era. This doesn't likely mean that the multi-coloured Daleks are gone, because all Daleks in this story predated the multi-coloured versions introduced in Victory of the Daleks.
 * As Clara leaves the school a clock can be seen to display the time as 17:16, the broadcast time of "An Unearthly Child".
 * The access code for the vortex manipulator is "1716231163". This is a reference to the time (17:16) and date (23.11.63) that the episode An Unearthly Child first aired.
 * When paired with the prequel episode The Night of the Doctor, the titles of both episodes reflect opposite moments in the Doctor's personal lifetime. Night depicts the Doctor giving in to despair after suffering an absolute failure, whereas in Day, he has an absolute triumph. The two episodes also bookend the War Doctor's lifetime. Night shows his birth, and Day shows his death, as well losing and regaining his title of "the Doctor".
 * The archived footage shown during the Save Gallifrey scene for the different Doctors are as follows:
 * The First Doctor's footage is from The Daleks.
 * The Second Doctor's footage is from The Tomb of the Cybermen.
 * The Third Doctor's footage is from Colony in Space.
 * The Fourth Doctor's footage is from Image of the Fendahl.  
 * The Fifth Doctor's footage is from Frontios.
 * The Sixth Doctor's footage is from Attack of the Cybermen.
 * The Seventh Doctor's footage is from Battlefield, and Doctor Who.
 * The Eighth Doctor's footage is from Doctor Who.
 * The Ninth Doctor's footage is from Rose and The Parting of the Ways.
 * The footage from Colony in Space, Image of the Fendahl, and Battlefield have all been flipped to make it look like actual filming.
 * Archive recordings from Fury from the Deep, an unknown Third and Fourth Doctor serial, The Five Doctors, Battlefield, and Attack of the Cybermen are used to provide the past Doctor with dialogue.
 * This is the final televised story to feature the Eleventh Doctor in a fez.
 * The TARDIS interior set floor was raised from its normal height during the filming of the special to help Jenna Coleman's stunt double ride Clara's motorbike into the TARDIS.
 * While the Eleventh Doctor is hanging out of the TARDIS over London, the soundtrack playing was first used in Aliens of London and World War Three.
 * With the airing of this episode's special closing credits, the actors for the First, Eighth, Ninth, and Tenth Doctors have finally had their faces featured in in a form of credits for Doctor Who, along with the newcomer War Doctor. By extension, all faces of the Doctor up to the Eleventh Doctor have now been shown in either opening titles and/or closing credits.
 * For the War Doctor, the Tenth Doctor and the Eleventh Doctor, the events take place shortly before they regenerate. The War Doctor is seen regenerating at the end of the episode. Chronological evidence indicates the Tenth Doctor experiences this adventure during the period when he was on a "farewell tour" before his final adventure as depicted in The End of Time. Similarly, the Eleventh Doctor would regenerate in his next televised adventure, The Time of the Doctor. Interestingly enough, all three Doctors are living under the shadow of a prediction or expectation of their own death.
 * Conversely, the episode foreshadows the birth of the Twelfth Doctor, who arrives before his actual debut from the not-so-distant future to join his younger selves in transporting Gallifrey into another universe.
 * One Dalek fighter pod can be seen knocked away from the destruction of the Dalek fleet. This would support the idea that some Daleks could feasibly survive beyond the Time War. However, it should not be confused with the Dalek seen in Dalek, as no connection is made that would suggest this craft was piloted by the same Dalek who fell through time and space to crash-land on Earth.
 * The Day of the Doctor was given a higher pyrotechnics budget because of its anniversary special status, which allowed the production to feature much bigger explosions, The heightened explosive use can be witnessed during the Fall of Arcadia segments.
 * David Tennant's Tenth Doctor portrayal became notable for a spiky, modern hairstyle that he experimented with near the end of Series 2 and later became his Doctor's default hairstyle up to his regeneration story. Unusually, Tennant's hair was slicked down in this special, save for one moment when the War Doctor acknowledged the "Bad Wolf" in front of his successors and his hair was standing on end.
 * The promise of the Doctor as stated by the Tenth Doctor, "never cruel or cowardly", hearkens back to a line spoken fourteen years prior to the fiftieth anniversary in another story that Steven Moffat helmed for Doctor Who- the non-canon 1999 Comic Relief special The Curse of Fatal Death. After the twelfth incarnation of an alternate Doctor died, apparently resulting in his demise, his companion Emma said that "He was never cruel and never cowardly".

The War Doctor's Regeneration
The scene featuring the War Doctor's regeneration into the Ninth Doctor does not conclude with the emergence of the Ninth Doctor. It only shows hints of his face beginning to form, due the absence of Christopher Eccleston after a difficult decision not to reprise the role for the anniversary special. Steven Moffat later explained his reasons for cutting the scene short in an interview published in DWM 473. He cited the main reason for abbreviating the regeneration as “human decency” for Eccleston.

"It was one thing to include him among all the other archive Doctors, as they flew in to save the day -- in fact, it would have been disgraceful to have left anyone out -- but placing him in that scene might have given the impression he’d actually turned up for filming, which would have been crossing the line. Not taking part in the 50th was a difficult decision for Chris, taken after a lot of thought and with great courtesy, and not respecting his wishes would have been grossly unprofessional and disrespectful to a good man and a great Doctor. Number 9 may not have turned up for the celebrations, but there would have been no party without him.”"

However, this has not stopped fans from posting their own modified takes of the regeneration online, who were not satisfied with the original scene. One of these edits has received over 300,000 views since it was made available on 3 December, 2013 for demonstrating a professional effort to complete the regeneration. The video clip showcases an extended cut of the previous footage that completes the face morph from Hurt to Eccleston and visualizes a fully regenerated Ninth Doctor in his first moments aboard the TARDIS.

Production errors

 * There is a basic hair continuity error in the scene where Elizabeth and her duplicate catch up with the Tenth and Eleventh Doctors in the forest. As the two Elizabeths each kiss the Tenth Doctor, the Eleventh's quiff inexplicably escapes from underneath the fez — mostly when he is out of focus — and then is magically back under the fez when he's in tighter shots.
 * A similar hair error occurs with the Tenth Doctor when the War Doctor is exclaiming about the "Bad Wolf". After having his hair slicked down for the whole story, his hair suddenly stands on end in one shot with the Moment in the background, which inadvertently resembles the spiky hairstyle the Tenth Doctor wore in his final years.
 * When the Tenth Doctor has been kissed by Elizabeth in their wedding, his collar is up in one shot, and down in the next.
 * The brief glimpse of the of the Twelfth Doctor's console room shows the time rotor piping to be blue, while TV:Deep Breath reveals that he changes the piping to orange shortly after his regeneration.
 * A close-up of the screen of the Space-Time Telegraph shows that it refers to the Brigadier's last name as "Left-Bridge" Stewart.
 * When all thirteen incarnations of the Doctor arrive to hide Gallifrey in a pocket universe, the Seventh Doctor first appears in his yellow pullover with question marks. When he appears again, his costume changes to the one he wore in the TV Movie and he is now in the Victorian parlour console room. When he appears for the third time, he goes back to wearing the pullover he originally wore in the television series. This emphasises that the archive footage used to generate his presence among the other Doctors has been pulled from asynchronous moments of his life, the early and late periods to be exact.
 * At the end of the special, when the three Doctors are in the museum, the Tenth Doctor asks what the painting is actually called. In that shot, the door to his TARDIS is open. In every shot after that, the door is closed.
 * When Clara enters the Eleventh Doctor's TARDIS and shuts the door, as the Eleventh Doctor starts thinking aloud he could retire and be "the great curator", Jenna Coleman can still be seen moving around inside the police box prop through a gap between the doors for about a second.
 * The last scene of the special, where the Eleventh Doctor is walking out of the TARDIS onto the cloud with his other incarnations, the TARDIS door handle has been obviously removed.
 * The closing credits credit Billie Piper as playing Rose, however dialogue in the episode (plus copious interviews and promotional material related to the special) clearly indicates that Piper does not play Rose in the episode, but rather The Moment, a clearly defined stand-alone character, and in the form of the Bad Wolf entity.
 * After the War Doctor's TARDIS ploughs down a group of Daleks in Arcadia and takes flight, the SFX incorrectly show it as the untarnished Eleventh Doctor's TARDIS complete with the St. John's Ambulance logo, when the practical War Doctor's TARDIS prop has been heavily battle-damaged.
 * In addition to this, a later shot of the Eleventh Doctor's TARDIS flying through space is clearly a reuse of the same footage.


 * When the Eleventh Doctor says "we're going to freeze Gallifrey" to the war council, Matt Smith's script can be seen on the TARDIS console.

Deleted scene

 * A short deleted scene on the BBC Doctor Who website features the War Doctor, the Tenth and Eleventh arriving at the Tower of London in ankle shackles. The Eleventh says his shoes "bring the cool" and that the Tenth "wouldn't understand the cool", whilst the exasperated War Doctor declares they haven't drawn breath "since Richmond".

Continuity

 * A police officer walks by a sign for I.M. Foreman's scrapyard at 76 Totter's Lane. (TV: An Unearthly Child) This indicates that the scrapyard appears to still be in business into the modern day, having last been seen in 1985. (TV: Attack of the Cybermen)
 * Clara is now a teacher at Coal Hill School. A sign shows that I. Chesterton is chairman of the school's Board of Governors.
 * Clara rides a motorbike into the TARDIS console room. A policeman from San Francisco previously rode a motorbike into (and very quickly out of) the TARDIS. (TV: Doctor Who) The Tenth Doctor similarly rode a moped out of the TARDIS (TV: The Idiot's Lantern), and the Eleventh Doctor did the same with a motorbike (TV: The Bells of Saint John).
 * While the TARDIS previously showed dislike for Clara, Clara is now able to close the TARDIS doors with just a snap of her fingers, suggesting it has grown to like her after saving the Doctor from the Great Intelligence. (TV: The Rings of Akhaten, Hide, Clara and the TARDIS, The Name of the Doctor) Previously only the Doctor in his most recent incarnations had been able to do this. (TV: Forest of the Dead, The Eleventh Hour, Day of the Moon)
 * The Eleventh Doctor continues to wear Amy Pond's reading glasses. (TV: The Angels Take Manhattan, The Snowmen, The Rings of Akhaten)
 * The Eleventh Doctor continues preferring odd reading material; this time it's Advanced Quantum Mechanics. (TV: The Wedding of River Song) For some reason, the cover of the book has an image of the TARDIS in its police box disguise.
 * Kate asks Osgood to tell "Malcolm" to change the batteries in the robotic ravens outside the Tower of London, and later calls Malcolm to request some of her father's files. This could be Malcolm Taylor, a UNIT scientist the Tenth Doctor met during his time on San Helios with the Swarm. (TV: Planet of the Dead) Kate previously made a seemingly-joking comment to Amy Pond about having "ravens of death". (TV The Power of Three)
 * The Doctor again uses the phone on the outside of the TARDIS (TV: The Bells of Saint John) It had previously not been a real phone. (TV: The Empty Child) He later tells Handles to remind him to rewire it back through the console (TV: The Time of the Doctor), though he later apparently had not done so (TV: Time Heist).
 * Romana said previously that, on Gallifrey, paintings are done by computers. (TV: City of Death)
 * The Time Lords in the War Room mention that the High Council are holding an emergency session, and that they have plans of their own. (TV: The End of Time)
 * The War Doctor's statement "No more" in relation to the Time War was also said by Dalek Caan after he saw the Daleks through all of Time and Space. (TV: Journey's End)
 * Upon viewing the Moment's controls, the War Doctor asks "Why is there never a big red button?", which the Moment later modifies itself to incorporate. The Tenth Doctor previously mentioned he could never resist pressing a "great, big, threatening button". (TV: The Christmas Invasion)
 * Like the Doctor's TARDIS when it inhabited Idris, The Moment is confused between the past and the future. (TV: The Doctor's Wife)
 * The Tenth Doctor marries Elizabeth I. (TV: The Shakespeare Code, The End of Time, The Beast Below, Amy's Choice, The Wedding of River Song) Presumably, the fact that he indicates no intention of returning to his new wife is what results in her antagonism towards him when she next encounters him thirty years later in 1599. That encounter, however, happened earlier in his personal timeline, so he had no idea why she wanted his head. (TV: The Shakespeare Code)
 * A painting of the Tenth Doctor wearing Elizabethan clothing, including a large collar, is shown alongside a portrait of Elizabeth I's. Although Elizabeth I married the Tenth Doctor, she met both the Tenth and Eleventh Doctors. While investigating a time anomaly in Victorian London, there was a statue of the Eleventh Doctor in Elizabethan clothing. The Eleventh Doctor said that Elizabeth I had made him wear the clothing, which he thought was for a private portrait. (GAME: The Eternity Clock)
 * The Tenth Doctor referred to his wedding to Elizabeth I when answering the summons of Ood Sigma (TV: The End of Time), who had appeared to him some amount of time previously (TV: The Waters of Mars). During the gap, he travelled around for a bit to try to avoid his fate. He tells a rabbit he is 904 years old here, while he told Ood Sigma he was 906. This suggests that, like the Eleventh Doctor's 200-year farewell tour (TV: Closing Time) but much shorter, the gap lasted several years.
 * The Fourth Doctor and UNIT previously fought the Zygons. (TV: Terror of the Zygons)
 * The Tenth Doctor previously encountered the Zygons in the Lake District in September 1909 in the company of Martha Jones. (PROSE: Sting of the Zygons) The Eleventh Doctor encountered them when he took Amy Pond and Rory Williams on an anniversary trip to the Savoy Hotel in 1890. (TV: The Power of Three)
 * While the Doctor is entranced by a fez, the painting that Clara stops to admire in the Under Gallery shows the latest variant of the Cybermen. (TV: Nightmare in Silver)
 * The Tenth and Eleventh Doctors try "Reversing the polarity", a catchphrase his third incarnation used.
 * The War Doctor doesn't recognise his Tenth and Eleventh incarnations, believing them to be companions. The Fifth Doctor didn't recognise the Tenth, and believed him to be a fan. (TV: Time Crash)
 * The Eleventh Doctor once again displays his habit of giving other people nicknames based on their appearance; calling the Tenth Doctor "Matchstick Man" and later "Sandshoes", while calling the War Doctor "Granddad", just as he did with Amy Pond, Rory Williams and River Song in the White House. (TV: The Impossible Astronaut)
 * The War Doctor calls the Eleventh Doctor's bow-tie a "dicky bow", criticising the fashion choice as Amy Pond and Rory Williams had before. (TV: The Eleventh Hour, Amy's Choice, The Lodger)
 * When Clara exclaims that "there's three of them", Kate replies "We have a precedent for that." (TV: The Three Doctors)
 * When the twelve Doctors contact the War Council to confirm they're ready to put Gallifrey into a pocket universe, the General complains "I didn't know when I was well off! All twelve of them!". This echoes Brigadier Lethbridge-Stewart's "Three of them, eh? I didn't know when I was well off!" (TV: The Three Doctors).
 * When Kate realises there are multiple Doctors, she asks Malcolm for one of her father's files code-named Cromer, which is a reference to her father at first believing the anti-matter universe to be Cromer. (TV: The Three Doctors)
 * She tells him it may be filed under the 70s or the 80s "depending on the dating protocol".


 * When surrounded by Queen Elizabeth I's soldiers, the War Doctor asks the Tenth Doctor and the Eleventh Doctor if they were going to "assemble a cabinet at them". The phrase "build a cabinet" was previously used by River Song in relation to the sonic screwdriver (TV: Day of the Moon), while the Ninth Doctor asked Jack Harkness if he'd "never had a lot of cabinets to put up" when Jack asked him about the sonic. (TV: The Doctor Dances) Ironically, the three Doctors later used their screwdrivers offensively to blast a Dalek back with a force field, destroying it.
 * The War Doctor gripes at his future incarnations for brandishing their sonic screwdrivers as if they were water pistols. The Tenth Doctor actually used a water pistol against the Pyroviles. (TV: The Fires of Pompeii)
 * The Eleventh Doctor calls to Clara through a wormhole, referring to her as the "Wicked Witch of the Well". Hila Tacorien was previously referred to by this name due to the wormhole in Caliburn House. (TV: Hide)
 * The Black Archive of UNIT appears. (TV: Enemy of the Bane, COMIC: Don't Step on the Grass)
 * The War Doctor and his successors were haunted over the 2.47 billion children of Gallifrey they killed by using the Moment. When the Eleventh Doctor took Amy Pond to Starship UK, he was moved by the sound of children crying. (TV: The Beast Below)
 * The Tenth Doctor asks the Eleventh where he's going, to which the Eleventh Doctor replies, "Spoilers". (TV: Silence in the Library / Forest of the Dead et al.)
 * Kate encounters an alien which duplicates her appearance and impersonates her. This had previously happened when a Dæmon statue had taken her shape. (HOMEVID: Dæmos Rising)
 * When a Zygon is killed disguised as another creature, it keeps the form of that creature. (HOMEVID: Zygon: When Being You Just Isn't Enough)
 * When the War Doctor enters the Tenth Doctor's TARDIS he says he really "let it go"; the Eleventh comments that this was his "grunge phase". The Eleventh Doctor then loads his own 'desktop', changing the TARDIS design. The Tenth declares he doesn't like it. The Second Doctor said the same when he saw the Third Doctor's TARDIS (TV: The Three Doctors) and the redesigned UNIT HQ (TV: The Five Doctors), as did the Eleventh Doctor when visited Craig Owens in his new home. (TV: Closing Time) The Fifth Doctor also disliked the Tenth Doctor "changing the desktop theme" when they accidentally ran their TARDISes into each other. (TV: Time Crash) The TARDIS told the Doctor that she archived past and future versions of the console room in The Doctor's Wife. While changing the theme the Console Room briefly features a hybrid of the Tenth Doctor's Console Room and the original TARDIS roundel design which is later seen to be the War Doctor's TARDIS theme.
 * The Doctor's various selves having difficulty getting on with each other when they meet. (TV: The Three Doctors, The Five Doctors, The Two Doctors, Time Crash)
 * Many alien artefacts from previous adventures are seen in the Black Archive, including River Song's red heels (TV: The Time of Angels), Magna-Clamps, (TV: Army of Ghosts/Doomsday), the head of a Supreme Dalek (TV: The Stolen Earth/Journey's End), a Dalek tommy gun (TV: Evolution of the Daleks), the restraining chair from the Naismith mansion (TV: The End of Time), the Space-time telegraph (TV: Terror of the Zygons), the sonic probe used by an older version of Amy Pond (TV: The Girl Who Waited), the facemask of one of the Clockwork Droids (TV: The Girl in the Fireplace), Amy Pond's pinwheel (TV: The Eleventh Hour), a Sontaran blaster, the half part of a Silent, the head of a Cybus/Cyber Legion Cyberman, and a TARDIS coral.
 * The Tenth Doctor, when returning to his own timeline, tells the Eleventh Doctor that he is glad his "future is in safe hands". These are the exact same words the First Doctor says to the Fifth Doctor upon the former's departure. (TV: The Five Doctors)
 * The security protocol for the Black Archive involves a self-destruct triggered through nuclear warhead detonation at the sacrifice of all human life in the blast radius. A similar nuclear option against alien attack was developed by UNIT in the form of the Osterhagen Project and was also nearly activated. (TV: The Stolen Earth, Journey's End)
 * When the Doctor calls from the TARDIS phone, his telephone number once again is 07700900461. (TV: The Stolen Earth)
 * This episode greatly resembles the events of The Fires of Pompeii; primarily, the sequence depicting the three Doctors placing their hands on the Moment resembles the scene in where Donna and the Doctor blow up Mount Vesuvius. In both cases, the Doctor was agonising over a terrible decision (Pompeii or the world; Gallifrey or the universe), but somebody came to support him, and share the responsibility of pressing the button. These two stories also resemble each other in that the Doctor's companion convinces the Doctor to take a different path rather than resigning himself to an unalterable consequence. (Donna convinced him to save Caecilius and his family; Clara convinces the Doctor to save Gallifrey without destroying the Time Lords).
 * The Eleventh Doctor refers to his fate on Trenzalore. (TV: The Wedding of River Song, The Name of the Doctor, TV: The Time of the Doctor)
 * The Tenth Doctor, upon hearing of Trenzalore, says they need to take a different direction as "I don't want to go." His successor notes that "He always says that", as it was his last words before his regeneration. (TV: The End of Time)
 * Prior to regenerating, the War Doctor comments that his body is "wearing a bit thin", repeating the line spoken by the First Doctor immediately prior to his own regeneration into the Second Doctor. (TV: The Tenth Planet). He then hopes that "the ears are a bit less conspicuous this time"; the Ninth Doctor makes a reference to the size of his ears when meeting Rose. (TV: Rose)
 * An eccentric, Doctor-like character who went by the name "the Curator" appeared in the story Summer Falls, which was marketed as being written by Amelia Williams.
 * While making the treaty, one of the Kate Stewarts can be heard saying "Look what happened to the Sycorax." (TV: The Christmas Invasion)
 * The Tenth Doctor tells the Eleventh Doctor "Oh, don't start" when he says "hello" to the Queen Elizabeth's, recognising it as the same trick Captain Jack Harkness often pulled- flirting with people from the moment he said "hello" - one he repeatedly stopped. (TV: Bad Wolf, TV: Utopia)
 * The forgetfulness of the Tenth Doctor, caused by the out-of-sync timelines, explains why the Doctor didn't recognise himself when he saw himself in Prisoner Zero the day he  regenerated into the Eleventh Doctor. (TV: The Eleventh Hour)
 * When the Tenth Doctor declared that Queen Elizabeth was a Zygon and Eleven confirmed this by saying he checked with the tongue, the Tenth Doctor told him to shut up. Later when Missy said she was a Mobile Intelligence System Interface and the Twelfth Doctor said she looked very realistic, Clara noted the tongue as Missy had missed the Doctor, to which Twelve said shut up. (TV: Dark Water)

Home release

 * The Day of the Doctor was released in the UK on Region 2 DVD, and Region B 3D Blu-ray on 2nd December 2013. The Night of the Doctor was also included on both versions. A Region 1 DVD and a Region A Blu-ray 3D/Blu-ray/DVD combo pack was released in the US on 10th December 2013.