 Michael O'Sullivan, the ruthless but honorable enforcer for a crime syndicate, is personally betrayed by his masters and is forced to flee with his young son Michael, Jr. on a quest for revenge.The story is set in the American Midwest during the Great Depression and draws upon several historical figures, especially the gangster John Patrick Looney, of Rock Island, Illinois; in real life, Looney came into conflict with Dan Drost, a formerly loyal lieutenant in their crime organization, and their feud eventually led to the death of Looney's son Connor.This story had many inspirations, such as the Japanese manga series "Lone Wolf and Cub", the American gangster John Patrick Looney, and various gangster films such as "The Godfather" and "The St. Valentine's Day Massacre".