Manny the mammoth, Sid the loquacious sloth, and Diego the sabre-toothed tiger go on a comical quest to return a human baby back to his father, across a world on the brink of an ice age.

Manny, Sid and Diego discover that the ice dam protecting the valley they were residing in was about to fall and eventually lead to floods. Soon after, they scamper off to find a safer habitat.

Manny and Ellie are expecting their first child, while Diego plans to move out. Meanwhile, Sid invites trouble by stealing some dinosaur eggs, causing the others to come and save him.

Scrat causes a monumental disaster when his nut chasing leads to a continental drift. Once again, Manny, Diego and Sid experience an adventure while trying to return home.

Scrat accidentally sets off an asteroid to Earth while trying to get his acorn. However, Manny, Sid and Diego must join forces with Buck to prevent the asteroid from wiping out their existence.

Buck, Crash, and Eddy try to keep the Lost World from being overtaken by dinosaurs.