The daybreakers
(Book, Reference)

Orrin and Tyrel Sackett are forced to leave their home in the Tennessee mountains when Tyrel shoots Long Higgins, after he accidentally shoots Orrin's bride-to-be. Higgins is the last of a family with which the Sacketts have been feuding. To keep from getting into a situation with the local sheriff, a distant cousin of the Sacketts, the two strike out for the western lands. With Cap Roundtree and Tom Sunday, the brothers settle in the town of Mora, New Mexico, and sent for the rest of the family. Orrin marries Laura Pritts, whose father, Jonathan Pritts, comes West with the idea of taking land from the Spanish who own most of the big grants. When his attempt to do so by political means fails, he tries force. Tyrel has married Drusilla Alverado, the daughter of a powerful, Spanish land owner. Orrin must choose which side he's on, his father-in-law's or his own clan. For his part, Tyrel is faced with a dilemma when his friend, Tom Sunday, turns bad and begins gunning for him. Time period: 1870-1872.