Human astronauts Burke and Virdon, with their chimp companion Galen, are forced to become involved in the strange gladiatorial games of the district run by prefect Tolar. The trio escape the gorilla police and find an abandoned government research project with a computer containing a vast amount of recording information about the old human-ruled world. [The second of five telefilms edited from episodes of the 1974 TV series; this film combines the episodes "The Gladiators" and "The Legacy"]