In a quiet suburban street, in a nice middle-class suburb, a vicious killer stalks. Behind the face of a respected, well-liked man, a loving husband and father hides the mind of a sadistic, cold-blooded serial killer responsible for the torture-deaths of more than two dozen children and young men.

Police Lieutenant Joseph Kozenczak, assigned to a routine disappearance case, begins to suspect that this pillar of the community has something to hide. Suspicion turns to obsession as Kozenczak is pressured by his superiors to give up the investigation while he is locked in a taunting cat-and-mouse game with the calculating John Wayne Gacy (Brian Dennehy). Even as the tenacious detective closes in, Gacy plots his next unspeakable act, sizing up his next victim.