Astronaut George Taylor, along with his crew, crash lands on a desolate, unknown planet in the distant future after a long space mission. They find themselves in a bizarre world where they are unable to communicate and are at odds with the environment. After trekking through a desert, they encounter a society where humans are mute and primitive, and intelligent apes are the dominant species. The apes have developed a civilization with their own system of government, culture, and particularly, a class structure where orangutans are the ruling elite, chimpanzees are the scientists and intellectuals, and gorillas are the military force and hunters.

Taylor is captured by the apes and taken to their city, where he stands out due to his ability to speak. He catches the interest of two chimpanzee scientists, Zira and Cornelius, who are sympathetic to him. While trying to understand and navigate through this upside-down world, Taylor discovers the disturbing history of the planet and starts to question the nature of humanity and its place in the universe. His struggle for survival becomes not just a physical battle but also an ideological one, as he confronts the prejudices and injustices of the ape society.