When eighteen-year-old Chance Morgan kills another shapeshifter to save his girlfriend, Ana Hughes, he contracts a dangerous shapeshifting sickness that makes him crave power uncontrollably-and without restraint he's a threat to the person he loves most. Desperate to keep Ana safe from harm and to find a cure for himself, he abandons her in the Yucatan and escapes into the wilderness. Violent memories and voices surface in his head, creating a dangerous tug-of-war between good and evil. Companionless and alone, Ana meets a woman who claims to have the same shapeshifting and healing abilities as her and vows to teach Ana the skills to help Chance, but as weeks pass she begins to question if her new mentor truly intends to keep her promise. With time running out, Ana must find the power within herself to heal Chance before he loses his battle against the powerful voices inside his head.