Enredo

In a futuristic world that has embraced ape slavery, Caesar, the son of the late simians Cornelius and Zira, surfaces after almost twenty years of hiding out from the authorities, and prepares for a slave revolt against humanity.

Cornelius and Zira's son Caesar leads apes to revolution in this installment of the apes saga. Dogs and cats have been wiped out by a plague and now apes are household pets that are treated like slaves. Caesar has the intelligence to fight this oppression.—Josh Pasnak <chainsaw@intouch.bc.ca>

Fourth feature in the simian series has apes domesticated and turned into work slaves in the near future. Along comes Ceasar, son of Cornelius and Zira who died in the third film, who leads his chimp brothers in rebellion against the human oppressors, thus creating the time loop that leads to the first film.—Humberto Amador

Following a North American pandemic from a space-borne disease that wiped out all dogs and cats in 1983, the government has become a series of Schutzstaffel-patterned police states that took chimpanzees, gorillas, and orangutans as pets before establishing a culture based on ape slave labor. These events were foretold in 1973 as testimony by two chimpanzee scientists who came from the distant future, Cornelius and Zira, before they were killed. Widely believed to be dead, their baby was secretly raised by the circus owner Armando as a young horseback rider. In 1991, now fully grown and named Caesar, the ape is brought to one of the cities to distribute flyers for Armando's circus. During their trip, Armando advises Caesar not to speak in public for fear of his life.

After seeing a gorilla being beaten and drugged, Caesar shouts "Lousy human bastards!". Armando attempts to defuse the ensuing commotion by taking responsibility for the exclamation. He plans to turn himself in to the authorities and bluff his way out while instructing Caesar to hide among the apes for safety. Caesar obeys and hides in a cage of orangutans, finding himself being trained for slavery through violent conditioning. He is then sold at auction to Governor Breck. Caesar is then put to work by Breck's chief aide MacDonald, whose African American heritage allows him to sympathize with the apes to the disgust of his boss.

Meanwhile, Armando is interrogated by Inspector Kolp, who suspects his "circus ape" is the child of Cornelius and Zira. Kolp's assistant puts Armando under a machine that psychologically forces people to be truthful. Realizing he cannot fight the machine, Armando jumps through a window and dies. When Caesar learns of Armando's death, he loses faith in human kindness. In secret, he begins teaching the apes combat and has them gather weapons.

Unfortunately, Breck eventually learns that Caesar is the ape the police are hunting. Meanwhile, Caesar realizes MacDonald is an ally to the apes' cause and reveals himself to him. MacDonald understands Caesar's intent to depose Breck, but expresses his doubts about the revolution's effectiveness. Caesar is later captured by Breck's men and is electrically tortured into speaking. Hearing him speak, Breck orders Caesar to be killed. With MacDonald's help, the heroes manage to trick Breck into believing Caesar died. Once Breck leaves, Caesar kills his torturer and escapes.

To build his numbers, Caesar takes over Ape Management. While setting the city on fire, Caesar and the rest of the apes proceed to the command center, killing most of the riot police that attempt to stop them in the process. After succeeding in this, Caesar has Breck marched out to be executed. MacDonald pleads with Caesar not to succumb to brutality and be merciful to the former masters. Caesar ignores him, deciding to dedicate his life to man's downfall.

This is the original uncut ending of the movie. After a bad reception from the first audiences due to its dark tone, the ending was reworked to add a dubbed follow-up to the speech from Caesar:

As the apes raise their rifles to beat Breck to death, Caesar's girlfriend Lisa voices her objection, saying "No!". She is the first ape to speak other than Caesar, but the other apes are concerned about Caesar's bloodlust as well. Caesar reconsiders and orders the apes to lower their weapons, deciding that they can afford to be humane, since the fight is already won and they "have seen the birth of the planet of the apes".