Evelynn Tanner, the local preacher's daughter, has made one too many mistakes. Apparently, marching into a brothel to confront her unfaithful beau is considered unacceptable behavior for an unwed young lady, and her father has turned her out of his home! Evelynn must now find a means to support herself. Her cousin, Broderick Tanner, is a Pinkerton Agent, and she manages to convince him that she'd make an excellent addition to the agency's female ranks. After all, Broderick's wife, Cecily, is a Pinkerton as well.

On the train ride to Denver, Evelynn meets Graham Morgan, another agent – and an irritating one at that. In the midst of an argument, she falls off the back of the train, and Graham selflessly jumps off to save her. Evelynn quickly finds herself falling for this charming protector, but will he be true to her? Or is he really just another dishonest snake like the last man she'd loved?