Chuck Norris, six-time World Karate Champion, stars in his first suspense film as the tough, street-fighting sheriff of a small Texas town terrorized by a psychotic killer. Sheriff Stevens (Norris) is faced with the dilemma of stopping the invincible murderer, made virtually indestructible through genetic engineering. A young group of researchers are responsible for developing the genetically altering serum, and the head of the research institute is determined to continue the experiments, regardless of the consequences. Norris displays fighting brilliance as he single-handedly routs a dozen brutal bikers from a truck stop hangout, while revealing a warm and sexy side when he rekindles an old romance with Alison Halman (Toni Kalem), a researcher at the institute. Excitement, horror, and romance prevail as Norris combats the killer.