Where is the Doctor? When the skies of Earth are frozen by a mysterious alien force, Clara needs her friend. But where is the Doctor, and what is he hiding from? As past deeds come back to haunt him, old enemies will come face-to-face, and for the Doctor and Clara survival seems impossible. The Doctor is an alien Time Lord from the planet Gallifrey who travels through all of time and space in his TARDIS. His current travel companion is Clara Oswald, though he has a long list of friends and companions who have shared journeys with him. Instead of dying, the Doctor is able to "regenerate” into a new body, taking on a new personality with each regeneration. Eleven actors, plus John Hurt, have played the Doctor thus far.