With her crew vanishing mysteriously, Captain Briggs assumes the Doctor is the guilty party, but the traitor is closer to homeā¦ as are the Cybermen.
Quest roles:
Matthew Waterhouse(Adric), Mark Hardy(Cyber Lieutenant), James Warwick(Scott), Clare Clifford(Kyle), Beryl Reid(Briggs), June Bland(Elizabeth Rawlinson), Alec Sabin(Ringway)