"Twice Upon a Time" is an episode of the British science fiction television series Doctor Who, written by Steven Moffat, directed by Rachel Talalay, and was broadcast as the thirteenth (and to date final until 2023) Christmas special on 25 December 2017 on BBC One. It features the final regular appearance of Peter Capaldi as the Twelfth Doctor, the first official appearance of Jodie Whittaker as the Thirteenth Doctor, and guest-stars David Bradley as the First Doctor, having previously portrayed original First Doctor actor William Hartnell in the 2013 docudrama An Adventure in Space and Time. Pearl Mackie guest stars as the Twelfth Doctor's former companion Bill Potts, while his other companions make guest appearances – Jenna Coleman as Clara Oswald and Matt Lucas as Nardole.
This episode is a continuation of events after "The Doctor Falls", addressing the cliffhanger that it ended on, and takes place during the final serial of the First Doctor, The Tenth Planet (1966), which ended with the introduction of the concept of a Doctor regenerating; footage from The Tenth Planet is used in the special. "Twice Upon a Time" is Capaldi's fourth and final Christmas special as the Twelfth Doctor, and the last Doctor Who story to be written and produced by Moffat, who had served as the show's executive producer and chief writer since taking over from Russell T Davies in 2010. After the special's broadcast, Moffat was succeeded as executive producer and showrunner by Chris Chibnall. It is also the last episode until the 2023 specials to have music composed by Murray Gold, who had composed music since the series' revival in 2005 and was succeeded by Segun Akinola in Series 11. The special has received generally positive reviews from critics.
Plot
Synopsis
Wandering back to his TARDIS through the South Pole in 1986 after leaving his companions behind, the First Doctor refuses to regenerate. He encounters the Twelfth Doctor outside his own TARDIS in a similar state of mind. The pair are soon approached by a confused and injured First World War British captain (Mark Gatiss), displaced from December 1914 while in a gun-point stalemate with a German soldier. All three are then forcibly taken into a large spaceship. Inside, they meet with Bill Potts. The Twelfth Doctor, however, doubts she is the real Bill. Upon encountering the ship's glass-like holographic pilot, they are offered freedom in exchange for allowing the ship to return the Captain to the moment of his death. Refusing to allow the Captain to die, they escape and take the First Doctor's TARDIS to the planet Villengard in the far future.
Alone, the Twelfth Doctor meets with the rogue Dalek Rusty, who has taken refuge from other Daleks hunting it. Given access to the Dalek Hivemind, the Doctor learns that the pilot and its ship, known as Testimony, were created on New Earth, designed to extract people from their timelines at the moment of their death, and archive their memories into glass avatars. "Bill" is one such avatar, created from her memories. Seeing no evil to fight, the Doctors agree to return the Captain to his timeline. Upon arrival, the Captain asks the Doctors to keep an eye on his family, introducing himself as Archibald Hamish Lethbridge-Stewart (implying that he is the ancestor of the Doctor's frequent ally and lifelong friend, the Brigadier, and his daughter Kate Stewart). As time resumes, the Doctors watch as soldiers on both sides begin singing "Silent Night". The Twelfth Doctor explains to the First that he deliberately shifted the Captain's timeline forward to the start of the Christmas truce, to ensure his life would be spared.
With the Captain saved, the First Doctor informs the Twelfth that he is now prepared to regenerate and says his goodbyes before returning to his TARDIS. He returns to the South Pole for Ben and Polly and finally regenerates into his second incarnation. Now alone with Bill's avatar, the Twelfth Doctor adamantly contends she is not really Bill, but she argues that memories are what defines a person. Bill's avatar restores the Doctor's memories of Clara Oswald before they are joined by Nardole's avatar. The Doctor, however, refuses to give the avatars testimony of his life. They respect his wish to be alone and leave after he embraces them both. The Doctor then returns to the TARDIS and decides to regenerate, but not before relaying some personal advice to his next incarnation.