It is Christmas Eve, and the Doctor is reunited with Wilf to face the return of an old enemy. Part of the BBC Christmas 2009 season.
This is the last story for lead actor David Tennant, who hands over the role of alien time traveller the Doctor to Matt Smith.
Bernard Cribbins, who appeared in the story “Voyage of the Damned” and throughout Series 4 as Wilfred Mott, grandfather of Donna Noble, acts as the companion to the Doctor in this two-part story. The special also features the return of many other actors to the show, including Catherine Tate, John Simm, Jacqueline King, Alexandra Moen, Billie Piper, Camille Coduri, Freema Agyeman, Noel Clarke, John Barrowman, Elisabeth Sladen, Tommy Knight, Jessica Hynes and Russell Tovey.
The story features the Tenth Doctor (Tennant), who has been running from a prophecy of his impending demise, as he is drawn into a scheme by his old nemesis, the Master (Simm). The Master brings the human race under his control as part of an elaborate plan to restore to the world his and the Doctor’s own people, the Time Lords, from their demise in the Time War referred to in the series. The Doctor is able to avert this, but incurs fatal injuries. In the episode’s conclusion, as has happened before, the Doctor regenerates and becomes a new man—with a new personality and physical traits—setting up the show’s forthcoming series of episodes with Matt Smith as the star and Steven Moffat as executive producer.