Duke Fergus falls for Ann 'Flaxen' Tarry in the Barbary Coast in turn-of-the-century San Francisco. He loses money to crooked gambler Boss Tito Morell, goes home, learns to gamble, and returns.

Legend has it that if the famous Barbary Apes leave the Rock of Gibraltar, it's a sign that the British will lose control of it. During World War II, a British officer is put in charge of the apes.