Two mini-episodes, The Night of the Doctor and The Doctor and the Last Day, were released just before the episode, depicting events during the Time War. The Night of the Doctor features the Eighth Doctor’s regeneration into the War Doctor. The Last Day depicts the fall of Arcadia, a central battle of the Time War, through a camera implanted in a soldier’s head.

In the war between the Time-Lords and the Daleks, the War Doctor (John Hurt) discovers an ancient, sentient weapon called The Moment which can destroy both sides. It has taken the shape of Rose Tyler (Billie Piper) and shows what the War Doctor’s future will be like when he is the Last Time Lord. She opens a fissure in which the War Doctor meets the Tenth Doctor (David Tennant) and the Eleventh Doctor (Matt Smith) in 1562 England. The Zygons enter Time-Lord paintings and emerge in the National Gallery in the present, taking the shape of UNIT soldiers so they can use UNIT weapons kept in the Tower of London.

UNIT head Kate Stewart (Jemma Redgrave) starts a countdown for a nuclear warhead beneath the Tower that will destroy the enemy by destroying London. The Doctors are unable to land the TARDIS in the Tower, so they use a stasis cube to enter a painting. They exit the painting and use UNIT’s mind-wiping equipment to make both UNIT and the infiltrating Zygons unable to tell which is which. Thus, they are forced to negotiate a peace treaty.

The War Doctor is convinced that detonating the Moment will save more lives in the Galaxy than letting the war continue. He returns to his Time with the other two Doctors. Clara insists they do not destroy their own people. Gathering all of the Doctor’s incarnations, they plan to use stasis technology to freeze Gallifrey in a pocket universe. When Gallifrey disappears, the Dalek weapons will be in a crossfire situation and obliterate themselves.

After Gallifrey disappears, the Doctors and Clara return to the Gallery, not sure if the plan worked. They will not be able to remember what happened and will remain feeling guilty. The War Doctor begins to regenerate, but we don’t see all of the process because Christopher Eccleston declined to appear. The Curator of the Gallery (Tom Baker) hints that the plan did work, as one of the three-dimensional paintings entitled Gallifrey Falls is now titled Gallifrey Falls No More. The Eleventh Doctor vows to find the hidden city.

The episode is rife with references, many of them to the First Doctor, William Hartnell, his granddaughter Susan Foreman, the Coal Hill School, the scrapyard where the TARDIS first appeared, and to many other Who icons along the way, like Brigadier Lethbridge-Stewart (Nicholas Courtney). Clips from early black and white episodes were produced in colour. The Tower of London UNIT Headquarters has photographs of all the companions, a lot of Dalek tech, and Captain Jack’s Vortex Manipulator. There are references to The Three Doctors and The Five Doctors, reversing the polarity, etc. The episode is a treasury of fan-service in-jokes. There is even a glimpse of the as yet unknown Twelfth Doctor’s eyebrows. It was filmed in 3D and thus took longer to film than usual. It received 100% on Rotten Tomatoes, was nominated for a Hugo, and was voted the Most Popular Story in Doctor Who History by Doctor Who Magazine.

John Hurt did not need to audition. He was asked to play the War Doctor and agreed immediately. Robin Williams had been offered the role but had to turn it down for health reasons. Delia Derbyshire, after fifty years, finally got credit for arranging the Doctor Who Theme. The only copy of the script was kept in Steven Moffett’s safe. The Moment (Billie Piper as Bad Wolf) was an ancient Gallifreyan doomsday weapon but helped convince the Doctor not to destroy Gallifrey. Funny, how a society as decadent and corrupt as the Time-Lords produces a weapon more moral than they are. David Tennant’s last words in the episode: “I don’t want to go.” Kate Stewart’s mobile phone plays the TARDIS sound when the Doctor calls. Clara was teaching at the Coal Hill School.

The show was aired in 94 countries. The theatre versions were preceded by shorts featuring Strax lecturing viewers on theatre etiquette and Matt Smith and David Tennant showing them how to put on 3-D glasses. Lord Bentham was a reference to Jeremy Bentham, co-founder of the Doctor Who Appreciation Society. Just why the Archivist looks like the Fourth Doctor is not explained. Tom Baker said he was mostly ignored on set, though he got along very well with Matt Smith. Colin Baker was miffed that Tom Baker was asked to be in it, but he wasn’t. But they left 43 seconds for applause when Tom Baker appeared on the screen, and Colin Baker would not have gotten that.