In Sioux Falls, South Dakota, young mothers become prey for a sexual sadist who stalks them, using homemade 'tire-poppers' to force them off the roads and into his clutches. Investigators must follow a lengthy trail of evidence, including hair on a piece of torn duct tape, half a nightshirt, a receipt for fingerpaint and a three-year-old eyewitness, to catch a killer before he strikes again. In the end, Robert Leroy Anderson seals his own fate with a damning jailhouse confession that leads them to his treasure trove of macabre trophies.