Carlos Saldanha and Mike Thurmeier's third helping of the family-friendly prehistoric animated adventure sees Manny the mammoth, Diego the sabre-toothed tiger and Sid the sloth journey far from the frigid world they call home. When Sid discovers a nest of apparently abandoned eggs in an icy cavern, he jumps at the chance to claim them and raise the nestlings as his own. He's not even put off when they turn out to be Tyrannosaurs, though his companions aren't so keen. But when the rightful mother returns to claim her brood, she takes Sid with her back down the tunnel. Diego and Manny mount a rescue and, as they progress deeper underground, discover an alien world that's not only hot but also ruled by dinosaurs. Luckily a mad weasel called Buck pops up just in time to save their skins.