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?

Intent on seeing the Cahulawassee River before it's turned into one huge lake, outdoor fanatic Lewis Medlock takes his friends on a river-rafting trip they'll never forget into the dangerous American back-country.