When heiress Audrey Hardwick is given the opportunity to become a Pinkerton Agent, she wholeheartedly leaves her life in Cincinnati behind and sets out for a new adventure. But her mission turns into mayhem when she meets Agent Warren Rockwell, a former gunslinger, who is too stubborn – and handsome – for his own good. Will she succeed in proving her worth as an agent, and as a woman, or will Warren always view her as his reluctant partner?

As one of Pinkerton's top agents, Warren must marry the hard-headed Hardwick due to a new rule that has been implemented at the Denver office: Newly hired female agents must marry an agent for their first case assignment. Audrey's beauty and her pampered background has him so frustrated that he doesn't know whether to scold her... or just kiss her good and hard.