Two mini-episodes written by Steven Moffat, "The Night of the Doctor" (14 November 2013) and "The Last Day" (21 November 2013), were released shortly prior to "The Day of the Doctor", depicting in-series events occurring during the Time War between the Doctor's own race of Time Lords and his nemesis, the Daleks.
She and the Doctor die as the ship crashes on Karn.
The Doctor is resurrected temporarily by the Sisterhood of Karn (who control a secret Elixir of Life in the 1976 serial The Brain of Morbius).
They persuade the Doctor to take action to end the Time War, offering him a selection of potions to control his regeneration.
He reluctantly accepts that with all of reality threatened and the universe "on the brink", there is not much need for a doctor, and chooses a potion designed to initiate his regeneration into a hitherto unknown incarnation of the Doctor as a "warrior" (described in credits as the "War Doctor" and played by John Hurt).
"The Last Day" is filmed from the first-person perspective of a Gallifreyan soldier who has had a camera implanted in his head.
The soldiers scan for Daleks at Arcadia, Gallifrey's second city and believed due to its impregnable defences to be the safest place on the Time Lords' home planet.During training exercises, a blurred object in the sky is identified shockingly as the first of a fleet of successfully invading Daleks, which kill the soldiers.The "Fall of Arcadia" becomes the central battle of the Time War around which "The Day of the Doctor" is centred.The 77-minute episode shows the last day of the Time War, in which the War Doctor (John Hurt) chooses to kill both Daleks and his own race of Time Lords to end the destructive conflict, paralleling this with a present-day choice by paramilitary organisation UNIT to destroy London rather than allow an alien invasion.Revising the back story, the Doctor succumbs to Clara Oswald's plea to change his mind; and instead, at the last instant of the Time War, he hides his war-racked home planet in time, rather than destroy it.Unfortunately, the time distortions incurred leave his past selves with no memory of his changed decision.