With the impending ice age almost upon them, a mismatched trio of prehistoric critters – Manny the woolly mammoth, Diego the saber-toothed tiger and Sid the giant sloth – find an orphaned infant and decide to return it to its human parents. Along the way, the unlikely allies become friends but, when enemies attack, their quest takes on far nobler aims.
When the farmer's away, all the animals play, and sing, and dance. Eventually, though, someone has to step in and run things, a responsibility that ends up going to Otis, a carefree cow.
A young man finds out that he holds the key to restoring hope and ensuring survival for the human race, while an alien species called the Drej are bent on mankind's destruction.
