 A hot spell is drifting through San Juan, and with it comes gangster Rufus Morgan, who has vowed to take over Carlos  casino. As a favor or repayment for some old air conditioners he donated to the convent, Carlos devises an arrangement, in paper only, with the convent through Sister Bertrille: he is deeding the casino to the convent while Morgan is in town, to be deeded back to him after Morgan leaves. In the meantime, Carlos goes into hiding. Although Carlos  assistant Pedro is running the casino in Carlos  absence, Morgan strong-arms Pedro into getting an official from the convent, that being Sister Bertrille, down to the casino to run things. She does so and gets conned by Morgan into playing in a table stakes poker game. He figures he can win the casino through this method. But the seemingly naive sister out-bluffs Morgan and wins everything she previously lost back. Despite this, the gig is up when Morgan catches Pedro conferring with Carlos on the telephone. The highly superstitious Morgan changes his plans for taking over the casino when Sister Bertrille hovers above his yacht telling him to lay off Carlos. Morgan believes that the vision he is seeing is an omen to get out of San Juan.