Grace and Jonathan Fraser have the life they've always wanted: she's a successful therapist, he's an acclaimed pediatric oncologist, and their son attends an elite private school in Manhattan. But for Grace, everything unravels overnight with a violent death and a missing husband.

Country vicar Merrily Watkins is in training to be an exorcist, or "deliverance counselor," for the Church of England. Although guided by the sardonic, no-nonsense Reverend Huw Owen, Merrily contends with self-doubt in her tough new role. When Merrily is called in to consult on a grisly murder investigation, the inexperienced exorcist finds herself battling supernatural terrors that threaten to overwhelm her.