Young Al Capone (Ben Gazzara) catches the eye of Johnny Torrio (Harry Guardino), a criminal visiting New York from Chicago. Torrio invites Capone to move to Illinois to help run his Prohibition-era alcohol sales operation. Capone rises through the ranks of Torrio's gang and eventually takes over. On top, he works to consolidate his power by eliminating his enemies, fixing elections to his advantage and getting rich. In his spare time, Capone courts the principled Iris Crawford (Susan Blakely).