 Chicago, 1920: Gangster Sam Dunleavy has just returned to town, and is visited by Al, a former childhood friend who is now a police officer. Al knows that Sam s girlfriend has just dropped him, and he warns Sam not to try anything violent. But Sam does plan to kill his ex-girlfriend, and he knows he needs an alibi. He sees his friend Barney, who promises to give him a perfect alibi for $2500. They work out the details, and Sam returns to Barney s place later to put the plan into action. But Al also shows up, so Sam knows that the plan must work perfectly.