Ice Age: The Meltdown
Manny, Sid, and Diego are currently living in a large valley surrounded by an enormously high ice wall on all sides which is actually a wall barely holding a massive body of water that could flood the valley. To be safe, they have to come to a boat at the other end of the valley within 3 days. Along the way, they are joined by Ellie, a mammoth who thinks she is a possum, and her possum brothers Crash and Eddie. But Scrat, the sabre-toothed squirrel, has his own adventures that eventually leads to something else entirely.