The romantic Black Mask has been slipping into London houses stealing and revealing secrets of evil deeds and stealing jewels which were often given to the poor. When Rose is kissed by the Black Mask at a masquerade party, she finds herself dreaming about the masked man. She decides to lure the Black Mask to her house and hire him to retrieve her brother's gambling IOU's so he will not be ruined. This has a spunky heroine and a romantic hero.
All of London is agog with the deeds of the daring Black Mask, a notorious jewel thief who also seems to have something of a social conscience. For, because of the Black Mask's daring deeds, a well known and rich member of society who was guilty of terrible crimes was exposed and forced to leave the country. Is the Black Mask some sort of Robin Hood? Or a mere thief who just happened to help expose one terrible man? That is the question that is being heatedly debated in the London drawing rooms. Rose Spenser, however has other matters on her mind. Finally in London in order to enjoy her Season, and to (hopefully) find a husband that her family will approve of and she can respect and admire (even though she's secretly hoping that she will find a husband that she will be passionately in love with), much of Rose's enjoyment of the London swirl of balls and entertainments is being dimmed by her discontented brother's (Rupert) rash behaviour.
Rupert wants to join the army. But their father, afraid that his only son will be killed in battle, has forbidden Rupert to do so. So that while the young man will not go against his father's wishes, his deep unhappiness about his situation has caused him to join a slightly wild set of young men who gamble for high stakes. And now, Rupert is deeply in debt to Sir Niles Alardyce, a much sought after bachelor who has a reputation for being rather supercilious, and whom Rose rather dislikes.