Miss Dinah Ashmore has a problem. Her sister has gone missing, and the constable isn't taking it seriously. She decides to take matters into her own hands by hiring a Bow Street Runner, not understanding the danger she has put herself in.

Nathaniel Calvert, Earl of Hawthorne, is an agent of the Crown. His assignment is to root out a radical group and bring them to justice. When Miss Ashmore mistakes him as a Bow Street Runner and explains her plight, he suspects that the missing sister might be connected to his case.

As Nathaniel works to stop the threat on the Crown, he realizes that Dinah isn't content with just being brushed aside. She is determined to be part of the effort to bring her sister home, no matter what the costs are. When Dinah's actions cause her life to be threatened, Nathaniel must keep her safe as he attempts to ignore their growing attraction. And when the truth is finally revealed, will Dinah be able to accept Nathaniel's lies and trust that love will conquer all?