Burke, Virdon and Galen come across two humans fighting and get involved, but lose the magnetic disc. To recover it, they must approach the nearby village, where the ape prefect pits humans in a series of gladiatorial games.

Burke and Virdon are helped by a young woman and a young boy while searching for an underground computer in a ruined city, but their plans go awry when Alan is captured and Urko uses the boy to get information from the astronaut.