As a kid living in Africa, Jill Young watched her mother killed while protecting gorillas from poachers led by Andrei Strasser. Now an adult, Jill cares for an orphaned gorilla called Joe -- that, due to a genetic predisposition that's 15 feet tall. After Gregg O'Hara arrives from California and finds that the creature that Jill convinces which Joe would be closest at his wild life refuge. But Strasser follows to the U.S., intent on capturing Joe because of himself.