The newly-regenerated Doctor helps UNIT battle a sentient robot being manipulated by a corrupt scientific organization.
Tom Baker
as The Doctor
Elisabeth Sladen
as Sarah Jane Smith
Ian Marter
as Harry Sullivan
Nicholas Courtney
as Brigadier Lethbridge-Stewart
John Levene
as RSM Benton
Patricia Maynard
as Miss Winters
Michael Kilgarriff
as The Robot
Edward Burnham
as Professor Kettlewell
Alec Linstead
as Jellicoe
Timothy Craven
as Short
Clive Barrie
as Phillips
Walter Goodman
as Joseph Chambers
