Set in 1964, a three-day journey along Route 66 begins when Bobby Falls, a 19-year-old serial killer, hitches a ride with Jim Goodwin, a celebrity animal handler travelling with his precious cargo: his TV chimpanzee, Spanky.

Caesar and his apes are forced into a deadly conflict with an army of humans led by a ruthless Colonel. After the apes suffer unimaginable losses, Caesar wrestles with his darker instincts and begins his own mythic quest to avenge his kind. As the journey finally brings them face to face, Caesar and the Colonel are pitted against each other in an epic battle that will determine the fate of both their species and the future of the planet.