During an attack on a pack of Iguanodon, an egg is separated and ends up with the possession of a group of lemurs. The lemurs care for this egg and the young creature born from it, which they call Aladar. When a meteor shower hits earth, Aladar and his family must leave their homeland. Away from home and as close to danger as they have ever been, they meet up with a huge group of dinosaurs, led by Kron and Bruton. All together they are trying to reach the nesting grounds, but it's not going to be easy.