Frannie Darling, a product of the London streets, works as a bookkeeper in an infamous gentleman's club managed by Jack Dodger. One night as she is leaving through the back of the establishment, she is accosted. She removes a hidden knife and makes a stabbing motion...Unfortunately, the Duke of Greystone was in the area and thought to come to her rescue. He pulls the man away just as Frannie lunges with the blade and he is the one who is wounded. Out of guilt she nurses him back to health. Greystone knows he can never take her to wife, she'd never fit in with his crowd, but she would make a most enticing mistress. And so he sets out to seduce her. But he'll discover that it isn't enough to have her in his life on occasion. He'll want her forever. But Frannie has never wanted to be part of the aristocracy. As secrets from her past and from his present are revealed, they'll both have to risk everything in order to claim the greatest prize of all: love.