20,000 years later Scrat is frozen in an ice cube that washes up on the shore of a tropical island. The sun slowly melts the cube, bringing Scrat back to life but the acorn, which is just out of his reach, ends up being washed away by the tide. Scrat then explodes out of the ice cube in anger and hits his head repetitively on a tree, which drops a coconut. Believing it to be a giant acorn, Scrat's anger immediately turns to glee at this new find. He tries to pack it into the ground as he did previously with his other acorns, but in the process causes a large crack in the ground that makes its way up the side of a volcano and causes it to erupt.
Meanwhile, Soto, the leader of a Smilodon pride wants revenge on a group of humans by eating the chief's baby son, Roshan, alive. Soto leads a raid on the human camp, during which Roshan's mother is separated from the rest and jumps down a waterfall when cornered by Soto's lieutenant, Diego. For his failure, Diego is sent to find and retrieve the baby. Sid and Manfred spot Roshan and his mother near the lake, having survived her plunge. The mother only has enough strength to trust her baby to Manfred before she disappears. After much persuasion by Sid, they decide to return Roshan but when they reach the human settlement, they find it deserted. They meet up with Diego, who convinces the pair to let him help by tracking the humans. The four travel on, with Diego secretly leading them to his pack for an ambush.