A wagon train of three families has hired mountain man Stephen Meek to guide them over the Cascade Mountains. Claiming to know a shortcut, Meek leads the group on an unmarked path across the high plain desert, only to become lost in the dry rock and sage. Over the coming days, the emigrants face the scourges of hunger, thirst, and their own lack of faith in each other's instincts for survival. When they encounter a Native American, they must choose between following their guide or an 'enemy.'