Thorn, a young she-wolf, lives with her family in a small pack. Though prey is scarce and the Two-paws are moving farther and farther into thier territory, Thorn and her pack are content with thier lives. But, as disaster looms over thier heads, Thorn must make a choice-move her pack over dangerous and deadly terrain to a new home, or stay and try to defend thier territory from the rising river and a rival pack that want to claim thier territory as thier own.