Dr. Howard Vanard (John Carradine) implants a strange electronic component into the brain of returning Vietnam War veteran Joe Corey (Roy Morton) who becomes a psychotic killer. Corey takes part in a jewel heist with a few cohorts, and while escaping from the scene, the stolen loot is hastily thrown from a rooftop into the back of a pickup truck belonging to a guy named David Clarke. After he violently murders a cocktail waitress in a motel room and a secretary who is working late in an office, Corey goes in search of Dr. Vanard, seeking revenge for what the old arthritic scientist has done to him. In a mindless rage, Corey straps Dr. Vanard to his own lab equipment and electrocutes the mad doctor. Corey and his friends then go to David Clarke's home and beat him up, trying to get him to tell them what happened to the stolen gems that were tossed into Dave's pickup truck, but they finally realize he knows nothing. Corey then follows David Clarke's wife Linda and his young daughter Nancy as they leave town on a trip. The young ladies unknowingly have the stolen jewels with them in their car, concealed in her daughter's doll. Corey chases the two through a snow-covered forest before being shot by a pursuing policeman. He falls off a cliff, clutching the doll and the jewels as he dies.