The Doctor and Romana try to avoid being sacrificed to Kroll – just in time for the real monster to appear.
Quest roles:
John Leeson(K9 (voice)), Terry Walsh(Crew Member (uncredited)), John Abineri(Richard Railton), Philip Madoc(Solon), Neil McCarthy(Thawn), Carl Rigg(Varlik), Frank Jarvis(Skart), Grahame Mallard(Harg), Mark Hardy(Cyber Lieutenant), Glyn Owen(Rohm-Dutt)