"On a winter day in 1910, at a train station in Ohio, two girls wait in the cold with their mother to begin a new life in the West. Tommy, the eldest, feels responsible for her sister, and in the years to come, as their mother campaigns for women's suffrage and teaches in one-room schoolhouses across Montana, she takes care of Katherine: trapping animals, begging, keeping house, cooking, while her sister goes to school. But as soon as Katherine graduates,...