The Ice Age is coming to an end and the animals of the Earth have taken warmly to the melting paradise that surrounds them. Despite the false comfort of a lush valley teeming with vegetation, however, great danger looms just over the horizon. When Manny, Sid, and Diego realize that the miles of liquefying ice overlooking their valley will soon turn from a gentle trickle to a violent force of nature capable of destroying anything and everything unfortunate enough to be in its path, they quickly set out to spread the word and get their endangered friends out of harm's way.