Mattie Lewis, wife of the stationmaster at Head of Echo Canyon in Utah in 1861, is trapped in an abusive and hopeless marriage, but vows to stick it how because she believes God hates divorce. Major Thomas Grafton, US Calvary, loves his job and admires Mattie from afar, but because she is the wife of another, he keeps his distance. When Mattie’s husband is killed during an Indian raid on the station, a bullet fired from the same gun Grafton carries is responsible. He is grieved, believing he fired the errant shot that killed Mattie’s husband, and vows to protect her and keep her safe, always fearful she may learn that he killed her husband. When the Pony Express sends a new stationmaster, Mattie is alarmed because he is her first husband, a man who abused her then abandoned her. She’d thought he was dead, but now learns that story was untrue. He wants to pick up where they left off, threatening to tell the major about her first marriage and the circumstances he had rescued her from. When she still resists, he threatens to concoct evidence to convict Grafton of murder. Will Mattie have time to make the right choice, or will the major be found guilty of a crime she doesn’t believe he committed?