Dr. X orchestrates the explosion of a plane to steal a nuclear warhead. With a nuclear battleship about to fall in Dr. X's hands, Action Man makes haste to recover the warhead, aided by his team and Dr. X's former lackey Ursula.

Action Man helps Knuck investigate his nephew Tom who has been involved in Gangrene's X-Vitamin steroid tests. Action Man tricks Dr. X into destroying Gangrene's lab and prevents him from putting the X-Vitamin into the city's water supply.