The battle between heaven and hell outside the human world is endless, and both sides are fighting for powerful fighters for themselves. CIA agent Simmons (Michael Jai White) is tired of the task of killing and asks his boss Wayne (Martin Sheen) to quit, but he is killed by Wayne while performing a mission in North Korea. Simmons, who fell into hell, reached an agreement with the demon Mariborgia and agreed to lead the army of hell for it in exchange for the opportunity to regenerate and take revenge. Simmons, who was hidden by the devil for five years, regenerated and returned to the world, showing himself as the Regeneration Man, and taking revenge on Wayne under the guidance of the devil's lackey, the Joker. At this time, Wayne, who is obsessed with studying biochemical weapons, tries to rule the world, and his death will cause the world to fall into a biochemical disaster. Can Simmons, who is seeking revenge, ignore the safety of all mankind?