Fourth Doctor's heroic efforts to protect Sarah Jane Smith, Harry Sullivan, and others despite relentless attacks and the sacrifice of personal connections and resources

The Doctor bursts from Kellman's smoke-filled cabin into pandemonium aboard the Transom to find Cybermen enforcing their brutal rule. Amid the mechanical tyranny and screams of the crew the Doctor …

The Doctor realizes a cybermat’s venom is poisoning Sarah just as the transmat rescue fails to activate, revealing deliberate sabotage. With time running out, he discovers Kellman’s betrayal is the …