After a marauding band of killers leaves Casey Storm afoot, his horse shot out from under him, he is forced to brave a high plains blizzard. Stumbling upon a wagon train of Montana settlers he falls in with them to help them fight their way toward the new settlement of Sundown. But, an army of gunmen hired by a land-hungry madman dogs their trail.The pursuing killers, approaching winter and an indifferent army all combine to block the wagon train's progress and any hope the settlers hold for a new life. Casey alone refuses to give up the battle even when the opposing elements collide explosively. Now, the dwindling calendar leaves them only six bloody days to reach Sundown. Will they win through and claim their land?