In order to avoid a marriage she doesn’t want, Clarissa Ferguson will have to get married to a man she doesn’t know.

Clarissa Ferguson craves a life of adventure. The last thing she wants is to become a socialite and marry a curmudgeon to appease her mother. When she sees an advertisement for female Pinkerton Agents, she leaves on the next available train to Denver Colorado. What she doesn't expect is to meet a handsome man on the train who ends up being her new trainer.

Noah Harding is recovering from the loss of his wife and family, and vows never to marry again. He throws himself into his work as a Pinkerton agent and has finally found a sense of purpose. He prides himself on being able to read people, that is until he observes a peculiar woman on a train headed west. What he didn't count on was that she is the newest Pinkerton Agent and he is required to marry her to solve a murder.

Will Noah be able to stay focused on the case with Clarissa distracting him? Will he be able to protect her when the case puts Clarissa's life in danger? When the case forces them to pretend to be something they aren't, what happens when their feelings become real?