Sacramento Homicide Detectives Harold “Harker” Smith and Dennis Steele are called to a horribly smashed corpse stretched on clean concrete behind a shopping center. They conclude a murderer stretched the unconscious victim around the front wheel and tire of a heavy vehicle, trussed him like a mummy with duct tape, then awakened him and slowly rollered him to death.
After The Steamroller Killer leaves his third messy victim, the police officers discover each man had a serious drinking problem and prior drunk driving convictions. Each corpse had been drugged and each had a new criminal jury trial for vehicular manslaughter on the court’s calendar.
Steele is promoted to lieutenant, and Smith gets a new partner. Susan Mosier soon learns Smith really doesn’t like females very much, and she struggles to impress him.
Smith eventually questions a suspect who lost his pregnant wife and toddler daughter to a drunk driver, but the District Attorney declares the evidence too slim for an arrest warrant.
The Steamroller Killer continues to leave grisly victims about the Sacramento area, bar owners complain of lost business, and police departments note a drop in DUI arrests.
Smith and Mosier create a plan which calls for the early release from state prison of the man who murdered their suspect’s family. They dangle him as bait and hope the killer does not change his modus operandi and execute the prisoner with the Magnum pistol they know he has.