Dakota Territory, 1867. The O'Driscoll brothers have survived a Sioux massacre, but Michael is gravely wounded. The deserters are fleeing north with Tom's lover, Sara, when they come upon a sheltering rock by a river down off the Bozeman trail. But their attempts to find food and endure the savage winter are threatened by the arrival of two trappers, whose presence sets in motion a series of bloody events that will mark the trio as outlaws, hunted by the Montana Vigilance Committee. The rock and the river become their safe place, and when spring comes, their paradise. But the world seeks its way to them, and even in paradise human nature makes its own trouble.