Ayleswick-on-Teme, 1813. Sebastian St. Cyr, Viscount Devlin, and his wife, Hero, have come to this deceptively peaceful Shropshire village to honor a slain friend. But when the body of a young widow is found on the banks of the river Teme, the village's inexperienced new magistrate turns to Sebastian for help. Sebastian soon realizes that Emma Chance was hiding her true identity, and she was not the first beautiful young woman in the village to be murdered. Also troubling are the machinations of Lucien Bonaparte, the estranged brother of the megalomaniac French Emperor Napoléon. Held captive under the British government's watchful eye, Bonaparte is restless, ambitious, and treacherous.

Home to the eerie ruins of an ancient monastery, Ayleswick reveals itself to be a dark and dangerous place with a violent past that may be connected to Sebastian's own unsettling origins. And as he faces his most diabolical opponent ever, he is forced to consider what malevolence he's willing to embrace in order to destroy a killer.