A grim incident from American pioneer history is recreated as a determined group of settlers, facing almost insurmountable odds, struggles to reach California in 1846. Already divided by internal dissension over the choice of a leader and the selection of a route, the wagon train is soon decimated by Indian raids, a scarcity of food and water, and the unrelenting forces of nature. Finally after months of hardship, the party reaches the High Sierras, only to be stranded in the middle of the pass by an early snowstorm. And as fear of an agonizing death from starvation forces the abandonment of conventional rules of human behavior, the pioneers face a new enemy - each other.