When the dinosaur families get trapped in a valley by an ice storm, one family of "spike tail" dinosaurs volunteers to leave since they consume more food than the others. Meanwhile, the young dinos and a new adult dinosaur named Mr. Thicknose, head out to bring back their friend Spike, who has left his friends to be with members of his own species.

Kate and Humphrey head out into the woods to look for food to stock up on for winter, and they leave their three pups with their parents. But the pups and the rest of the pack must venture out in search of them after the duo get caught in a blizzard.