Matt Smith (Eleventh Doctor)
Peter Capaldi (Twelfth Doctor)
Jenna Coleman (Clara Oswald)
Orla Brady – Tasha Lem
James Buller – Dad
Elizabeth Rider – Linda
Sheila Reid – Gran
Mark Brighton – Colonel Albero
Rob Jarvis – Abramal
Tessa Peake-Jones – Marta
Jack Hollington – Barnable
Sonita Henry – Colonel Meme
Tom Gibbons – Young Man
Ken Bones – Voice
Aidan Cook – Cyberman
Kayvan Novak – Voice of Handles
Nicholas Briggs – Voice of the Cybermen/Daleks
Barnaby Edwards, Nicholas Pegg – Daleks
Ross Mullan – Silent
Dan Starkey – Sontaran
Sarah Madison – Weeping Angel
Karen Gillan – Amy Pond
Directed by Jamie Payne
Written by Steven Moffat
Script editor Derek Ritchie
Produced by Marcus Wilson
Executive producer(s) Steven Moffat
Incidental music composer Murray Gold
Series Specials (2013)
Length 60 minutes
Originally broadcast 25 December 2013
Thousands of aliens orbit an unknown planet, from which a message no one can translate is continually being broadcast across time and space. The Doctor, drawn to the planet, uses a modified Cyberman head nicknamed "Handles" who tells him the planet is named "Gallifrey". The Doctor uses his TARDIS to collect Clara while she is having Christmas dinner with her family, and takes her to the Papal Mainframe, a space church orbiting the planet and headed by a former acquaintance of the Doctor, Mother Superior Tasha Lem. Tasha states they have constructed a force field around the planet to prevent the other aliens from landing, and offers the Doctor the opportunity to explore to find the source of the message.
On the planet, they discover a human settlement called Christmas where a truth field prevents anyone from lying. The message originates from the basement of a church, through a crack in reality, "scar tissue" from when the Doctor rebooted the universe. Handles identifies the message as Gallifreyan, repeating the question "Doctor who?" The Doctor deduces that his people, the Time Lords trapped in a pocket universe, are trying to escape into this universe and seek him to answer his true name to confirm this is the correct universe. However, their reappearance will inevitably start a new Time War, as all the aliens in orbit are enemies of the Time Lords. Tasha warns him that should the Time Lords try to escape, she will destroy the planet and anyone on it to prevent a new Time War, creating a stalemate situation for the Doctor.
When Tasha tells the Doctor this planet is named "Trenzalore", the place he knows he will ultimately die, he tricks Clara into getting something from the TARDIS, but instead sends her back to her time while he prepares to defend Christmas. Clara, furious at being tricked, jumps onto the TARDIS before it can dematerialise, and is returned to Trenzalore, discovering 300 years have passed. The visibly-aged Doctor reveals to her that his body has no further regenerations left, and is prepared to die here. The two are invited to Tasha's ship, discovering that in the intervening time, the Papal Mainframe have renamed themselves as the Church of the Silence, and that a chapter of the Church broke off to try to interfere in his past to prevent these current events. The Doctor discovers that Tasha and all her members have become Dalek puppets, attempting to lure him away. The Doctor manages to infuriate Tasha, allowing her to break the Dalek conditioning, and she helps them to escape back to the planet as the Dalek fleet amasses in orbit.
The Doctor manages to lie to Clara despite the truth field, and tricks her again to the TARDIS, which returns her back to Earth and dematerialises before she can react. Her family attempts to cheer her up but she remains dejected until she hears the TARDIS rematerialise a few hours later. She finds Tasha piloting the ship, and Tasha takes her back to Trenzalore, many centuries after the Doctor sent her away, insisting that no one should die alone. The Doctor, frail and senile, has held his defenses against a protracted siege on Trenzalore, but cannot stop a final attack from the Daleks. After saying goodbye to Clara, he goes out to the church steeple to face his enemies.
The Eleventh Doctor, about to die from old age, is granted a new regeneration cycle by the Time Lords, subsequently preventing his death.
Clara speaks to the Time Lords through the crack, begging them to help the Doctor and reminding that if he should die, the crack will close. The Doctor prepares to die outside, when the crack appears in the night sky. Regeneration energy flows from the crack and into the Doctor, granting him a new regeneration cycle and saving him from death. The Doctor uses the excess energy of his regeneration to destroy the Daleks, while the crack closes up, ending the stalemate.
In the aftermath, Clara finds him young again in the TARDIS console room. As he sets the TARDIS in motion, he explains that his youthful appearance is a "reset" for the new regeneration cycle to begin and the changing of his form is taking a while to start up. He delivers a eulogy to his current form, hallucinates a final farewell to Amy Pond, and regenerates. The Twelfth Doctor then declares that the TARDIS is crashing and asks Clara if she knows how to fly it.