In a forgotten corner of Wales, a young girl languishes in a home for troubled children. Abandoned by her parents because of her violent streak, Jessie, at the age of ten, is at risk of becoming just another lost soul in the foster system. Precocious and bold, Jessie is convinced she is possessed by the devil and utterly unprepared for the arrival of therapist Torey Hayden. Armed with patience, compassion, and unconditional love, Hayden begins working with Jessie once a week. But when Jessie makes a stunning accusation against one of Hayden's colleagues, a man Hayden implicitly trusts, Hayden's work doubles: now she must not only get to the root of Jessie's troubles but also find out if what the girl alleges is true.