The Doctor and Sarah answer a distress call and find themselves on Zeta Minor, the last planet of the known universe, where a Morestran expedition has gone missing.
Quest roles:
Terry Walsh(Guard (uncredited)), Michael Wisher(Ranjit (voice, uncredited)), Prentis Hancock(Salamar), Max Faulkner(Tribesman (uncredited)), Louis Mahoney(Ponti), Ewen Solon(Vishinsky), Frederick Jaeger(Sorenson), Graham Weston(De Haan), Terence Brook(Braun), Tony McEwan(Baldwin), Haydn Wood(O'Hara)