While Scrat the Saber-toothed Squirrel is still trying to find his precious acorn, the misfit trio of Manny the Mammoth, Sid the Sloth and Diego the Sabre-toothed Tiger have settled down in an isolated valley with numerous other animals. However, they soon discover that a huge glacial dam holding off oceans of water is about to break, threatening the entire valley. Their one chance of survival is a boat at the other end of the valley. While this unlikely...