Cassie hasn't felt this alone since she moved to New Salem and joined the Circle—the closest thing to a family she's ever known. But now that the Circle has been possessed by powerful evil spirits, Cassie is left with no choice but to turn to her dark side to rescue them. As she struggles to get through to her friends and her soul mate, Adam, she finds an unexpected ally—one who will tempt her more than ever before.

With her enemies quickly closing in, Cassie fights to keep her heart true and her soul pure. But she knows better than anyone that all magic comes at a price, especially when Black John's Book of Shadows is involved. Will Cassie defeat the darkness once and for all . . . or will the Circle be lost for good?