John Henry Irons is a weapons designer who invents high-tech equipment for the United States military. One soldier, Nathaniel Burke, decides to demonstrate Irons' weapons at the highest power setting, causing an accident that paralyzes Irons' partner, Sparky; as a result, Burke is dismissed from the military and Irons resigns. However, when Burke hatches a plot to mass-produce Irons' weapons and sell them to criminal gangs, Irons and Sparky join forces to stop him, creating a suit of armor used by Irons to become the superhero Steel.