William Darmon and wife Elizabeth were powerful figures who in 1818 set society's pace from expansive grounds known as Mayfair Hall. When a family member is murdered, a mysterious pendant is found containing a long lost request by Napoleon Bonaparte for an American mission to burn down Parliament buildings. The couple sets out on an action filled pursuit of the killer. While interviewing Henry Clay in post-war Maryland about the failed mission, they uncover evidence of a conspiracy to free the Emperor from exile. The Darmons infiltrate the cadre, but a shipwreck off the coast of Scotland, a firestorm at the Darmon's Manor and a harrowing assault on the Island of St. Helena loom before the mystery can be unraveled.