Young Treasury Agent Elliot Ness arrives at Chicago and is set to take down Al Capone, but because Capone has the authorities in his own pocket, it isn't going to become easy. Ness meets Jimmy Malone, a veteran patrolman and possibly the most honorable person . He requests Malone to help him get Capone, but Malone warns him that when he moves after Capone, he's going to war.