Snow falls in the Great Valley for the first time, puzzling and enchanting everyone. The friends search for Spike after he leaves to search for his family.

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.—Damaris