The fourth film in the sci-fi saga illustrates how the ape revolt happened in the first place. Caesar, played by series regular Roddy McDowall, gains the power of speech, forms enslaved fellow simians into guerrilla groups and leads them against the evil human race who have adopted them as household pets. Gritty direction from J Lee Thompson and plenty of fun philosophising, complete with intriguing moral lessons and neat ape/man role reversals (take a bow, Paul Dehn, for an uncommonly fine script), make this episode a compelling outing into futuristic monkey business.

In a futuristic world that has embraced ape slavery, a chimpanzee named Caesar resurfaces after almost twenty years of hiding from the authorities, and prepares for a revolt against humanity.