 A human-male named Farrow finds a crashed spaceship, goes inside, and discovers three astronauts -- one dead, two unconscious. He carries the two unconscious ones to his cave and, after they revive, shows them an old book with a photo of New York City in the year 2503. Shocked, the astronauts figure that while they left Earth in the year 1980, they ve somehow come back to Earth more than a thousand years later, and that apes now rule the planet! Farrow is killed defending the astronauts who are captured by apes, tried, and thrown into a cell. They escape in company with a sympathetic chimp named Galen and begin a series of adventures.