
The newly-regenerated Doctor helps UNIT battle a sentient robot being manipulated by a corrupt scientific organization.
Tom BakerThe Doctor
Elisabeth SladenSarah Jane Smith
Ian MarterHarry Sullivan
Nicholas CourtneyBrigadier Lethbridge-Stewart
John LeveneRSM Benton
Patricia MaynardMiss WintersMichael KilgarriffThe Robot
Edward BurnhamProfessor KettlewellAlec LinsteadJellicoeTimothy CravenShortClive BarriePhillipsWalter GoodmanJoseph Chambers
Jon PertweeThe Doctor