Sontaran Field Major Styre is conducting experiments on the survivors of future Earth in preparation of a full-scale Sontaran invasion of the planet. Can the Doctor defeat Styre and save the world?
Tom Baker
as The Doctor
Elisabeth Sladen
as Sarah Jane Smith
Ian Marter
as Harry Sullivan
Kevin Lindsay
as Styre / The Marshal
Donald Douglas
as Vural
Glyn Jones
as Krans
Peter Walshe
as Erak
Peter Rutherford
as Roth
Terry Walsh
as Zake
Brian Ellis
as Prisoner
