The Sisters brothers
(Book)

When a frontier baron known as the Commodore orders Charlie and Eli Sisters, his hired gunslingers, to track down and kill a prospector named Herman Kermit Warm, the brothers journey from Oregon to San Francisco, and eventually to Warm's claim in the Sierra foothills, running into a witch, a bear, a dead Indian, a parlor of drunken floozies, and a gang of murderous fur trappers.