The TARDIS arrives in 2070 on the Moon, where a weather control station under the command of a man named Hobson is in the grip of a plague epidemic — in reality the result of an alien poison planted by the Cybermen. Jamie is knocked unconscious and lapses into a delirium, leaving the Second Doctor, Ben, and Polly to fight off a massive Cyberman attack.

Patrick Troughton
as The Doctor

Anneke Wills
as Polly

Michael Craze
as Ben Jackson

Frazer Hines
as Jamie McCrimmon

Patrick Barr
as Hobson

André Maranne
as Benoit

Michael Wolf
as Nils

John Rolfe
as Sam

Mark Heath
as Ralph

Alan Rowe
as Voice from Space Patrol/Dr. Evans