When Amelia finds out her younger brother is a witch, they must flee-or die. The city of Malva is rife with puritanical hatred for witches, who are said to embody the Seven Deadly Sins of mankind. Amelia's only chance of saving Nathaniel, her brother, is to become a professed nun at Cathedral Reims, but doing so means enduring a series of trials: near-starvation, intense isolation, beatings, and blood-sucking leeches. Escalating these are shadowy beings only Amelia can see. After harming her best friend with fire, a witch's signature, she worries they are after her because she is a witch like her brother, who reveals he, too, can see them. Oliver Cromwell, a dashing priest at Cathedral Reims, confirms her fears. He tells Amelia that these beings are Shadowmen: dead, unredeemed witches, seeking witches like Amelia to join their ranks. When this group of rebel Shadowmen begin planning to destroy those who slaughtered them, Oliver is the only one who can protect Amelia and save Malva. Yet, he may prove to be more dangerous than the shadows themselves-and his love for Amelia fatal.