It's 20,000 years ago and there's a bit of a nip in the air as the Ice Age kicks off. Manfred the well-meaning mammoth, Sid the fast-talking sloth and Diego the duplicitous sabre-tooth tiger form a reluctant and unlikely alliance when they come across a helpless human baby. As they try to return the tot to his migrating tribe, the trio must battle more than just the elements in this harsh world of predators and prey. There's plenty of light relief from the dramatic tension and superb action sequences, notably in the form of the brilliant comic invention Scrat, an apparently insane sabre-tooth squirrel who steals any scene in which he--and his acorn—appear (although a flock of keen but hapless dodos give him a close run for the film's comic laurels).