After some time since the US Army was called to fight the power of an increasingly powerful and intelligent army of primates, the primate clan, led by the Caesar chimp, is attacked in the forest by the military faction known as Alpha-Omega. AO also has a primate service that was on the side of Koba, the one who has long tried to take over the Caesar primates. Several AO soldiers, including Red Gorilla, are captured and reveal that this unit follows the orders of a ruthless colonel.
Caesar releases prisoners as a sign of peace to people, but plans to relocate the clan beyond a desert because he does not want to lose more comrades. On the night before the trip, AO infiltrates the primates, and the colonel kills Caesar’s wife and their eldest son. Leaving his younger son behind, Caesar goes to seek revenge against the Colonel.
He is accompanied by the orangutan Maurice, the gorilla Luca and the Rocket chimpanzee, and the other primates are heading for the desert. Caesar and his comrades arrive at an AO camp, and there he finds out that the colonel has gone to a place known as the “border” … Caesar then kills without a traitorous gorilla and begins to worry that he becomes as violent as Koba. During their journey, they meet a man who lives in an abandoned village and kills him when he heads to the rifle. After discovering a little girl who seems incapable of speaking, Maurice insists on taking her with her to protect her.