Young Treasury Agent Elliot Ness arrives in Chicago and is set to shoot down Al Capone, however because Capone has got the authorities in his pocket, it's not going to become easy. Ness matches Jimmy Malone, a patrolman and also the most honorable one in the force. He inquires Malone to help him get Capone, but Malone warns him that if he goes after Capone, he's going to war.