Reginald, Marquess of Haddington, has been assigned to determine if a dangerous weapons dealer operating in the rookeries poses a threat to the Crown. It appears to be a straightforward case until he is also assigned to partner with Miss Ashmore, a beautiful but stubborn woman he has always loved.

Miss Evie Ashmore doesn't want a partner but is forced to accept Reginald's help. She is convinced that harm has befallen her mentor and is bound and determined not to rest until she ensures that he is safe, which forces her to visit the most unsavory parts of London.

As Evie and Reginald learn to work together, a greater danger looms and they quickly realize that everything is not what it seems. Can love truly conquer all, or was this doomed from the start?