Twelve-year-old Kex stows away in a lifeboat, hoping to see the world, but after being washed overboard he finds himself on an island where dinosaurs and humans coexist.
Littlefoot spoils Nibbling Day and blames it on a herd of tiny mussauruses. The adults get angry and set off an avalanche that opens a tunnel and allows two velociraptors into the valley. Everyone must work together to chase them off.