The action of the dramatic anime series "91 Days" takes place in the American town of Lawless during the time when Prohibition was in effect in the state of Illinois. During this time, bootleggers were thriving in the illegal liquor trade. Angelo Lagusa, a young man whose relatives were killed by members of a criminal gang, is plotting his revenge. He plans to seek vengeance against a mafia boss named Vanetti. After spending seven years on the run, Angelo suddenly receives a message from his father's friend.