The trio discovers a human that has built a crude glider. He is then captured by the apes, and one ape in particular wants to see the glider developed to its full potential... so that she can wipe out the gorilla and orangatuan leadership.

The trio encounter a village of humans that hand over their own kind to the apes to work as slaves. The "gods" kill anyone who violates the village law, but the leader's son has second thoughts when his fiancee is the next slave to be chosen.

The astronauts run into a village struck by malaria. Only their knowledge can end the disease... but the apes have other ideas.

The trio are forced to ally with Urko to bring down a tyrannical gorilla ruler in an outer province.

Urko and Zaius capture Pete and subject to him to brainwashing, and Galen turns to an old flame and his parents to help him and Alan rescue their friend.

A young human rides a horse to get an antidote to save Galen's life, even though it's against the law. When he's captured, Alan agrees to ride in a horse race against Urko's jockey to save the boy's life.

The trio investigates a village where a group of hooded ape Dragoons are terrorizing the humans after two humans allegedly killed an ape scholar. Things get complicated when the dead ape's blind daughter falls in love with Pete, unaware that he's a human.

When Alan is badly wounded by an ape bullet, Galen must convince his former girlfriend--a chimpanzee surgeon--to operate on his friend using a forbidden human medical textbook.

Pete and Alan rescue an old man left to die at sea, and are captured by a local labor center that needs the astronauts to work for them to fulfill their quota.

The trio find a long-buried human science institute, but the projector revealing the vault of hidden knowledge is out of power. While Pete and Galen collect parts to make a battery, Urko and Zaius capture Alan and try to obtain the institute's location from him.

After Galen breaks his leg, the fugitives are forced to take refuge with a family of poor ape farmers. The eldest son's cow is pregnant... and if it fails to deliver a bull, he'll hold the humans to blame and kill them.

While pursuing the fugitives, Urko is caught in an earthquake and trapped in an underground subway station... with Pete. To free them both, Alan and Galen must make a deal with Urko's lieutenant, Zako.

A chimpanzee prefect uses gladiatorial games to keep his human villagers pacified. However, the son of the undefeated champion won't fight... and the astronauts turn to him for help when the prefect acquires the disk.

Two Earth astronauts find themselves thrown through a time warp to Earth... over 500 years in the future where apes now rule the planet and humans are considered little more than dumb animals.