When the guys try to track down the apes who are framing humans for crimes in a small community, Fauna, a blind female ape, falls in love with Burke while believing him to be a chimpanzee.
Galen must use all his charm to try and persuade his ex-girlfriend, a female ape surgeon named Kira, to operate on Virdon using a forbidden human anatomy book, after the astronaut is shot.
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.
In a ruined city, Burke and Urko are trapped underground and must reluctantly work together to escape, while Alan and Galen must deal with Urko's gorilla patrol in the streets above.
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.
Astronauts Alan Virdon and Peter Burke crash land on a strange planet. After being rescued by a friendly human, Virdon and Burke discover this planet is ruled by intelligent apes. To their horror, they discover that they are back on Earth in the year 3085.