"Possessed by a demon...or by the urge to kill?"

Chicago is gripped by terror. The Sweet Sixteen Killer is brutally murdering sixteen-year-old girls, and the authorities are baffled.

A seemingly normal fourteen-year-old boy has attacked his entire family and had to be chained to his bed. His uncle, police officer Danny Hartman, is convinced his nephew is possessed by a demon. Danny has sent his partner, Jack, to fetch the only priest in Chicago who has ever performed an exorcism.

But Jack has other plans tonight. He believes the boy isn t possessed by a demon, but instead by an insatiable homicidal urge. Jack believes the boy is the Sweet Sixteen Killer. And he aims to end the reign of terror before another girl dies."