As a child living in Africa, Jill Young (Charlize Theron) saw her mother killed while protecting wild gorillas from poachers led by Andrei Strasser (Rade Serbedzija). Now an adult, Jill cares for an orphaned gorilla named Joe -- who, due to a genetic anomaly, is 15 feet tall. When Gregg O'Hara (Bill Paxton) arrives from California and sees the animal, he convinces Jill that Joe would be safest at his wildlife refuge. But Strasser follows them to the U.S., intent on capturing Joe for himself.