In the second episode of the four-part story "Robot," the Doctor (Tom Baker) tries to help the Brigadier (Nicholas Courtney) solve a series of crimes, all related to the disappearance of a new disintegrator gun. The Doctor's companion, Sarah (Elisabeth Sladen), believes that a robot is responsible for the crime wave -- and this insight may prove fatal to her. First telecast on January 4, 1975, "Robot, Episode 2" was written by Terrance Dicks. ~ Hal Erickson, Rovi