Taking place after astronaut Leo Davidson's adventure on the ape world, the anti-human forces of Shiva's ape army seek to exterminate the integrated human and ape resistance led by the chimp leader, Seneca, and the human, Esau. Meanwhile, a double-agent walks a dangerous line, working for the ape army while smuggling arms and provisions to the rebels. When this agent is exposed, secrets are revealed that force both sides into a race against time for the ultimate weapon in the war...and for the chance to rule the Planet of the Apes!