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. Norris is faced with the dilemma of stopping the invincible murderer, made virtually indestructible through genetic engineering. A young group of researchers is responsible for developing the serum, and the head of the research institute is determined to continue the genetic experiments regardless of the consequence. Norris displays fighting brilliance as he singlehandedly routs a dozen brutal bikers from a truckstop 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.