Planet of The Dead (Doctor Who)

"Planet of the Dead" is the first of four special episodes of the British science fiction television series Doctor Who broadcast in between mid-2009 and early 2010. It was simultaneously broadcast on BBC One and BBC HD on 11 April 2009. The specials served as lead actor David Tennant's final stories as the Tenth Doctor. He is joined in the episode by actress Michelle Ryan, who plays Lady Christina de Souza, a one-off companion to the Doctor. The episode was written by Russell T Davies and Gareth Roberts, the first co-writing credit since the show's revival in 2005. "Planet of the Dead" serves as the 200th story of Doctor Who.