Far to the north, the men of an isolated silver mining community are turning into vicious "beasts" that slaughter anyone in sight. The mines belong to the noble family of Prince Anton--ruler of Castle Sèone and Céline and Amelie's patron--and Anton's tyrannical father has ordered his son to solve the mystery as a test of his leadership. He has no choice but to send the witches into the perilous north to use their abilities to discover the cause of the transformations. Given how much they owe the prince, the sisters have no choice but to go.

Together with the overprotective Lieutenant Jaromir, Célene and Amelie enter the dark world of a far-off mining camp tainted by fear, mistrust, and enslavement--and haunted by men turning into massive mad wolves without warning. Now the two must draw upon strength and cunning they never thought they possessed not only to solve the mystery, but to survive....