One day, a swarm of "locust" descends upon the Great Valley, devouring all plants and reducing it to a barren wasteland. The inhabitants of the Great Valley have no choice but to find another place where they can survive until the plants have grown back. However, the leaf-gobblers have left a path of devastation behind them, leaving no food for the dinosaurs to find. After searching for many days, tension enters the group as Cera's father and Littlefoot's grandfather argue over changing their course, beginning a fight between Littlefoot and Cera. The fight immediately breaks up when Cera's father announces that every herd should go its own way the next morning. Not wanting to be separated, Littlefoot leads his friends off in the night, in the hope they can find food before they are caught. They leave a trail for the grownups to follow, and eventually reach the "ocean". Disheartened by the undrinkable water, the children spy a verdant island connected to the mainland by a thin land bridge. On their way, an earthquake occurs, which creates a tsunami from which they narrowly escape. They quickly tuck in to the plentiful bounty of the island, but are then horrified to discover the tsunami has destroyed the land bridge.