The ships crash-lands and the Doctor manages to escape out of the hatch. Stotz's men give chase, guns blazing. Salateen leads the soldiers through the tunnels. When they see an android, he walks boldly toward it, trusting the belt plate, but is gunned down. The Doctor is finally cornered by the gun-runners, but before they can kill him, mud bursts erupt, sending them fleeing back to their ship. Chellak and his soldiers don't have time to get behind the barriers, so they advance, wiping out most of Jek's androids. Jek tries to repair some but is chased off by Chellak. The gun-runners return to the ship to find Morgus there. Morgus has decided to wait and see if his role in events is discovered - then flee with his money and Jek's spectrox if he has to. Chellak and Jek fight in his headquarters. Chellak rips off Jek's mask and is horrified by what he sees, giving Jek time to shove him out the door into a burst of boiling mud. Peri sees Jek's face too and screams. Morgus contacts Krau Timmin to find that she's turned him in and taken over his company, making him a penniless fugitive. He still want to get Jek's spectrox store, but only Stotz agrees to go. After they leave, Stotz returns and guns down his remaining crew. The Doctor reaches Jek's lab to find Peri dying. Jek gives him directions to the lair of the queen bat and an oxygen cylinder and the Doctor climbs down into the lair and takes milk from the queen bat. But Stotz and Morgus find Jek's location. Morgus demands the spectrox and Jek rips off his mask, revealing a horribly scared face. He attacks Morgus and they struggle. Jek is shot by Stotz but the android Salateen returns and guns down Stotz. Jek finishes choking Morgus, then collapses into Salateen's arms. The air circulator bursts into flames but the Doctor retrieves Peri. He carries her across the exploding landscape to the TARDIS but loses some of the milk while opening the door. He makes Peri drink the bat's milk before collapsing. Peri recovers but the Doctor is fading fast. He sees the faces of his past companions, including Adric, telling him that he must live. Then he hears the Master's voice telling him to die. His vision goes up in a blaze of white and he wakes to find he has regenerated into a blond curly-haird man. Peri asks what happened and he replies, "Change my dear. And it seems not a moment too soon."