The Doctor and Sarah return to London but find the city deserted.
The Doctor and Sarah Jane Smith arrive in a deserted London plagued by looters and lawlessness. The United Nations Intelligence Taskforce is helping maintain martial law. The regular army, headed by General Finch, has evacuated the city and issued orders to shoot looters on sight. The Doctor and Sarah encounter several looters and a pterodactyl. The Doctor and Sarah Jane are arrested on suspicion of being looters.
Outside, a tyrannosaurus rex destroys a building and traps some soldiers. They drive it off. At UNIT HQ the Brigadier and Benton discuss the interference problems with their communications and look at the latest pictures of looters, which include the Doctor and Sarah.
The Doctor and Sarah escape but are caught by soldiers. They are loaded into the back of a jeep to be taken to the detention center. The jeep encounters a tyrannosaurus rex.