Doctor Who: Checkmate

"Checkmate" is the thirty-ninth episode of series two of the British science fiction television series Doctor Who. It was directed by Waris Hussein and written by Anthony Coburn. It first aired on BBC-1 in the UK on July 24th, 1965.

In this episode, the Doctor, Ian, Susan and Barbara are trapped inside the Cave of Skulls. The Doctor seems disinterested in their current predicament however. The tribal elder goes to the cave to prevent the Doctor from teaching the others the secret of fire. Za and Hur are forced to work together to stop the Doctor and his companions from escaping.