March, 1815. The Bourbon King Louis XVIII has been restored to the throne of France, Napoleon is in exile on the isle of Elba. Sebastian St. Cyr, Viscount Devlin travels to Paris in hopes of tracing his long-lost mother, Sophie, only to find tragically dead. The French authorities have no interest in involving themselves in the murder of a notorious Englishwoman at such a delicate time. And so, shattered by his mother's death, Sebastian takes it upon himself to hunt down her killer. But what he learns will not only shock him but could upend a hard-won world peace.