27 September 1975
Frederick Jaeger (Sorenson), Ewen Solon (Vishinsky), Prentis Hancock (Salamar), Graham Weston (De Haan) [1-3], Louis Mahoney (Ponti) [1-2], Michael Wisher (Morelli) [1-3], Terence Brook (Braun) , Tony McEwan (Baldwin) , Haydn Wood (O’Hara) [1-2], Melvyn Bedford (Reig) [3-4].
|Written by||Louis Marks|
|Directed by||David Maloney|
|Produced by||Philip Hinchcliffe|
The Doctor and Sarah land on Zeta Minor, at the very edge of the universe. A scientific team led by Professor Sorenson is being terrified by an anti-matter monster, a situation which deteriorates when Sorenson takes a sample of anti-matter off-planet.
The Doctor must stop Sorenson, who has begun mutating into a Jekyll-and-Hyde-like anti-man, and restore the balance on Zeta Minor before death comes calling for them all.