Jack Hall, paleoclimatologist, must make a daring trek from Washington, D.C. to New York City to reach his son, trapped in the cross-hairs of a sudden international storm which plunges the planet into a new Ice Age.

Manny, Sid and Diego discover that the ice age is coming to an end, and join everybody for a journey to higher ground. On the trip, they discover that Manny is not in fact the last of the woolly mammoths.