Prehistoric friends Manny the wooly mammoth, Sid the sloth, Diego the smilodon, Scrat the “saber-toothed” squirrel, and the rest of your Paleolithic pals are reunited in one big unforgettable icecapade in this series of “mini graphic-novels.”
As Scrat is inspecting snow to find a secure place for his acorn, Sid wakes Diego and Manny up to begin foraging and is flung into the air by Manny as Sid mistakenly stands on Manny's trunk, landing in a tree. The three move out, collecting grasses, while Scrat notices that a small chip of ice that he flung away is starting to snowball bigger and bigger; Scrat stops it as the herd continues to gather, but another small chip of ice rolls again, growing bigger until it rolls off a cliff and towards the herd, who drop their gatherings and run as fast as they can from the giant snowball.
With that, a large chunk of ice that Scrat is standing on breaks off, bringing everything crashing down, and the herd moves to escape the falling ice, escaping into a nearby cave, with Scrat's acorn landing on Sid's head as they run. The ice and snow fall on until it all blocks the cave entrance.
In the dark, Sid panics at the idea of running out of air and being eaten, before Diego reminds him of his fear of the dark and Sid, regaining composure, starts up a small fire with a rock. The fire, Diego notices, will not last long with the small sticks used as fuel and demands that Sid, who is running about with his tail on fire, come closer.
Meanwhile, Crash, Eddie and Peaches, missing their breakfast, all begin to wonder where Manny, Sid and Diego are, and Ellie decides to take Peaches and the possums to go out and find Manny, Sid and Diego. Back in the cave, Diego has shorn away almost all of Sid's pelt to feed the fire, leaving the sloth bare from the chest down, with Sid complaining aloud that Diego could have used Manny's fur instead.
Scrat, coming to after falling from the ice cliff, searches for his acorn and screams loudly once he realizes that it is gone. Ellie goes out with Peaches, Crash and Eddie, following Manny, Sid and Diego's footprints, which stop at the ice bank where the avalanche took place; Manny and the others, on the other hand, remain trapped in the cave, Sid eating the acorn that struck him on the head as Diego notices that the smoke from their fire is not filling up the cave and so has to be escaping from some opening: one at the top of the cave.
Outside, Ellie and the others notice the smoke coming from the sunken cave and reach the opening where it is emerging from: Sid calls out to them to move downhill to open the blocked entrance. At both sides, the herd digs: from inside the cave, Manny, Sid and Diego tunnel their way out while Ellie, Crash, Eddie and Peaches dig their way in; Scrat digging through the snow into the cave.
Both sides reach each other, and all are disgusted by Sid's now half-hairless body, moving on, away from the cave. Inside the cave, Scrat finds the empty shell of his acorn jubilantly, thinking that it is whole