When a charming 12-year-old girl takes on the characteristics and voices of others, doctors say there is nothing they can do. As people begin to die, the girl's mother realizes her daughter has been possessed by the Devil. Her daughter's only possible hope lies with two priests and the ancient rite of demonic exorcism.

Bizarre nightmares plague Regan MacNeil four years after her possession and exorcism. Has the demon returned? And if so, can the combined faith and knowledge of a Vatican investigator and a research specialist free her from its grasp?

On the fifteenth anniversary of the exorcism that claimed Father Damien Karras' life, Police Lieutenant Kinderman's world is once again shattered when a boy is found decapitated and savagely crucified.

Years before Father Merrin helped save Regan MacNeil’s soul, he first encounters the demon Pazuzu in East Africa.

Father Merrin takes a sabbatical from the Church to devote himself to history and archaeology as he struggles with his shattered faith.

Since his wife's death, Victor has raised his daughter Angela alone. After she and her friend return from a three-day disappearance with missing memories, they begin displaying frightening behavior reminiscent of the MacNeil possession fifty years prior.