Arriving on Space Station Nerva in its distant past, the Doctor, Sarah and Harry find its crew threatened by a mysterious plague. Discovering that things are not as they seem, they uncover a Cyberman plot to destroy Voga, planet of gold.
Tom Baker
Doctor Who
Elisabeth Sladen
Sarah Jane Smith
Ian Marter
Harry Sullivan
Ronald Leigh-Hunt
Commander Stevenson
William Marlowe
Lester
Kevin Stoney
Tyrum
David Collings
Vorus
Alec Wallis
Warner
