Fallon, the Marchioness of Mystery, finds herself embroiled in seduction and scandal when she is blackmailed into helping the handsome but dangerous spy Warrick Fitzhugh. He is out to hunt down the notorious crime lord responsible for the deaths of his fellow spies, and she is the only one who can help. As their quest leads them deep into London's treacherous underworld and face-to-face with their inner demons, they find the only ones they can turn to are each other.
