Young widow Annabel Chalfont, Countess of Fellbridge, has two small sons to raise, a mountain of her late husband's debts to pay off, and a secret: she's a shadow-shaper, able to manipulate shadow as anyone else might clay. She and six other high-born ladies with equally extraordinary abilities defend England against supernatural crime—but the world knows them only as the Lady Patronesses of Almack's, Regency London's most exclusive social venue.

Annabel's cousin Hartley has been shaken from his self-absorbed ways by Demetria Poulis, a bewitching Greek soprano who is taking London by storm. When a rash of jewel thefts seems to accompany her recitals, Annabel fears Demetria may not be what she seems. As it happens, she isn't—but a happily-ever-after for Hartley and Demetria isn't necessarily out of the question, thanks to the Ladies of Almack's...