Scrat is shown in the beginning of the movie, looking for a place to secure his acorn. In his attempt, he stomped the prized acorn on the ground causing avalanche. Scrat survives the avalanche but found himself in a stampede where dinosaurs steps on him and he is lost in the view.
Scrat ended the story when he wakes up in the current time and finds a coconut. He believes the coconut to be a giant acorn and tries to stuff it on a ground causing a crack on the floor eventually causing a volcano to erupt.