The Agent's Mail-Order Bride (Mail-Order Brides of the Southwest #6)
Heidi Vanlandingham

He has a crime to solve. She needs a new groom. Can she convince him he’s the right man for the job?
Reformed outlaw turned Pinkerton Agent, Matthew Tate is tasked to bring to justice the one man controlling a small Utah mining town. But when the female agent posing as his wife doesn’t arrive, he must scramble to find a woman to take her place while keeping his own life, both past and present, a secret.
Having lost everything after the War Between the States, Catriona Stewart travels west as a mail-order bride only to discover her groom has been murdered. She agrees to pose as a stranger’s bride but, when they end up legally married, she vows to discover who her new husband really is.