An energy drain traps the Third Doctor and Sarah Jane Smith on the planet Exxilon with its hostile natives, causing the travellers to make an uneasy alliance with a Marine Space Corps expedition and a squadron of Daleks. The key to escape for all of them lies at the heart of a powerful and mysterious lost city, but only after a series of deadly traps.
Jon Pertwee
The Doctor
Elisabeth Sladen
Sarah Jane Smith
Duncan Lamont
Dan Galloway
John Abineri
Richard Railton
Joy Harrison
Jill Tarrant
Julian Fox
Peter Hamilton
Neil Seiler
Commander Stewart
Arnold Yarrow
Bellal
