The death of a notorious London diamond merchant draws aristocratic investigator Sebastian St. Cyr and his new wife Hero into a sordid world of greed, desperation, and the occult, when the husband of Sebastian's former lover Kat Boleyn is accused of the murder. Central to the case is a magnificent blue diamond, the Hope diamond, believed to have once formed part of the French crown jewels. Set in Regency London: September, 1812.