Deep space, the distant future: following Earth's devastation by solar flares, the survivors of mankind are in cryogenic suspension aboard the Nerva Beacon space station. The Doctor, Sarah and Harry arrive on board just as the menace of the insectoid Wirrn becomes apparent...
Elenco: William Hartnell , Patrick Troughton , Jon Pertwee , Tom Baker , Peter Davison , Colin Baker , Sylvester McCoy .