Laura Elizabeth Woodbury, heir to a Montana cattle ranch, has just lost her father. A year ago, he bestowed upon her the nickname, "princess Sapphire" when he discovered sapphires in a mine where, sixteen years earlier, he'd found gold. The independent Laura is astonished to learn her father has hired a fancily-dressed stranger to assist her in finding a suitable husband, and to help run the ranch. Matt Black is the right hand man of a Minnesota railroad baron who'd been a friend of Laura's father. Matt's been hired to head up a team of railroad workers replacing damaged railroad tacks across Montana and to find a decent man to marry Laura. Matt is completely unprepared for the headstrong, willful blond and soon finds himself in love with her. Laura feels the same way about Matt-until she learns his secret that will change her life completely.