Ice Age

The film begins with a squirrel known as Scrat, who is trying to find a location to store his prized acorn. Eventually, as he tries to hide it, he causes an avalanche.

In the beginning, most animals are trying to avoid the ice age by migrating south. Sid, a clumsy ground sloth left behind by his family, is attacked by two Brontops whom he angered. Sid is soon saved by Manfred ("Manny"), an agitated mammoth who fights off the two Brontops. Not wanting to be alone and unprotected, Sid follows Manny.

Meanwhile, Soto, the leader of the Smilodon pride wants revenge on a group of humans by eating the chief's son, Roshan, because the humans had wiped out half of his pack. During the attack by the Smilodon pack on the humans, the baby's mother evades the cats who are pursuing her by jumping into a waterfall. With that, Soto orders Diego to find the baby and bring it to him alive.

Sid and Manny spot Nadia near the lake having survived her fall, having only enough strength to trust her baby to Manny before she disappears. After much persuasion by the sloth, they decide to return the baby (nicknamed "Pinky") but when they get to the human camp, the humans are gone. Diego convinces the pair to let him help by tracking the humans. The four travel on, with Diego secretly leading them to an ambush. Soon they reach a cave where Sid and Diego learn about Manny's past and his previous interactions with the humans.

At the end of the film, Diego, Manny and Sid battle Soto's pack and a short fight ensues. Diego fights against Soto, and Soto knocks Diego out. As Soto closes in for the kill on Manny, Diego leaps and stops Soto, who wounds Diego in the process. Manny, in vengeance, knocks Soto into a wall of rocks, where icicles fall and kill Soto. Manny and Sid manage to return the baby to his tribe, and Diego rejoins them, as the group begin heading off to warmer climates.

Years later, Scrat is shown on a tropical island, with a coconut to replace his lost acorn, but as he proceeds to pack the coconut, it causes a volcanic eruption.

Alert viewers will notice the plot has some similarity to Disney's animated version of The Jungle Book (1967), though it also has a lot of themes and jokes from Three Men and a Baby. During a speech given at the Tokyo Film Festival in 2006, producer Bill Mechanic stated, "I had been at Disney, we had success with Three Men and I thought we had picked the ice age as a good milieu, and then what story could we tell in there? And I thought the way to do it was Three Men and a Baby."

DELETED PORTION

Originally, Sid was trying to avoid another sloth named Sylvia. He manages to lose her by putting her in the path of some migrating glyptodons, who unknowingly carry her off when she got caught on their backs. Later he makes it look like Diego had killed him, but she saw he was faking, so she deserted him in anger. This segment was still used in the movie, but was used for Sid to avoid the two brontotheres who were still after him, as they fell for the trick. It was kept in the storybook version, however. The deleted scenes can be viewed separately, or in Nutty Movie Mode, both of which are included on Disc 1 of the two-disc Special Edition DVD.