J Lee Thompson's addition to the Apes... canon is the fourth entry. Set on Earth, apes are now the slaves of humans on the order of Governor Breck. But still hidden is Caesar, the intelligent, talking ape/human of the murdered Cornelius and Zira from Escape from the Planet of the Apes. Keeping his identity secret, it's only when Breck orders the torture and death of his friend Armando that he organises a bloody revolt against the humans with the hope of establishing a world where dumb humans are the slaves of intelligent, talking apes.