"Mrs." Elizabeth Rowland is the young housekeeper for a courtesan, Kitty Fleet, living on the edges of fashionable society. She lives vicariously through the excitement of her mistress's affairs, never dreaming that a very different sort of excitement is about to land on her doorstep -- literally. It's Christmas morning, chill and bright, and Bess Rowland steps out to sweep the front steps of snow only to find a dead lordling sprawled across her mistress's stoop, beaten bloody and holding what appears to be a dead wren. It isn't long before she has even more company: Besides a mysterious body, a Bow Street Runner by the name of Jim Watt appears, this address in hand, wondering if he's too late -- but for what?