Young Harley Cobb comes west after the Civil War and establishes himself in a good job at a flour grinding company in Boulder, Colorado. The girl he fell in love with on the way comes to join him so they can start a new life together. While his wedding is being planned, his employer sends him to Mishap Creek, Wyoming to buy a part for the mill. He gets into a fight, killing a gunman who is cheating and threatening four young cowboys over a game of poker. The man turns out to be the son of a wealthy and influential rancher.

Harley manages to escape a lynching and, with help from a deputy, jail. But his troubles are just beginning. The rancher becomes obsessed with finding and killing Harley, even to the point of letting his ranch go to ruin and hiring the best guns in the territory. Meanwhile, a pretty barmaid who saw the shooting rides to Colorado to get help from Harley's friends. They battle the rancher to a draw near Cheyenne, and then again, in a firefight in Mishap Creek.

Harley heads back to Colorado, now conflicted about new-found feelings he has for the barmaid. He decides the girl he truly loves is the one waiting for him in Boulder. They get married and Harley knows he made the right decision. He is the happiest he's ever been. But his past catches up with him when the rancher and three others find Harley and his new wife at home in Boulder. They come with nothing in mind but blood and terror. When the work of their vengeance is done, Harley descends into a darker place than he experienced even during the worst of the war.

With help from an old Chinese laundryman named Lin-Chi and his Cheyenne friend White Crow, Harley eventually finds his way out of the shadows. He undergoes a transformational change when he begins his own pursuit of vengeance. And along the way, he finds help from a new friend, an old, broken-down sheriff in Wyoming, and an old friend, the barmaid he met in Mishap Creek. He will need all the help he can get for the final showdown.