Ice age is the worlds most terrifying event that took place in history. As the Earth was being covered in ice and glaciers, lots of animals didn't survive because of lack of food. As the worlds largest migration starts, the audience gets to meet Manny, the mammoth, a sloth named Sid as well as the sabre-toothed tiger Diego. Manny doesn't want to have anything with the rest of the world, because of how his family had died. Sid, the sloth, is left behind by his family, because he is the clumsy and stupid one. And Diego was forced by his pack boss to go to a local village and grab the human child that was left behind. As Sid follows Manny no matter what, two of them become a kind of a pack. They come across the human child and decide to get it back to its pack, the humans who were already on their way. Soon, Diego manages to join in. His first idea was to trick them somehow into handing him over the child and to get his teeth on it. But, as that fails, he must infiltrate. Along the way, they start to grow on each other and become a pretty unique herd. They manage to return the child to humans and defend themselves from Diegos boss, who is more than eager to get the mammoth as a replacement for the child.