The legendary Joe, a playful, smart fifteen-foot-tall gorilla, and his lifelong best friend Jill Young (Charlize Theron) have grown up together in the remote mountains of Central Africa. When Joe's peaceful existence is shattered by poachers, Jill and zoologist Gregg O'Hara (Bill Paxton) rescue their innocent friend and move him to the safety of an animal conservancy in California. But Joe's safety is short-lived. No longer a myth, his notoriety makes him a target for an enemy from his past -- a ruthless hunter who will do anything to capture the Mighty Joe.