Kivu, an orphaned mountain gorilla, rules Silverback Valley in the extraordinary African rainforest. Under his watchful protection, the animals are kept safe, but then a storm brings a fierce crocodile who threatens the survival of everyone. Kivu decides to leave in search of a new life. He is not completely alone as the gentle Okapi goes with him, for like Kivu, she is the last of her kind.

Their epic journey takes them across the rainforest to the top of a volcano where they encounter a dangerous troop of baboons, intent on destroying the forest. To fulfill his destiny, Kivu must confront the baboons but also his old enemy, the crocodile.