After her fiance is killed, Cat Calder, a Montana rancher's daughter vows never to marry, but sex with a stranger is acceptable. The result is a son and years later when the stranger is appointed sheriff and she faces danger her vow is tested.

"Montana 1925: An Irish boy orphaned by Spanish flu, a tiny girl who won't speak, and a volatile young man who lies about his age to escape Hell's Kitchen, are paraded on train platforms across the Midwest to work-worn folks. They journey countless miles, racing the sun westward. Before they reach the last rejection and stop, the oldest, Charles, comes up with a daring plan, and alone, they set off toward the Yellowstone River and grassy mountains...