Duke Fergus, a strong Montana cattleman played by John Wayne, travels to San Francisco to collect $500 from Tito Morell, a sophisticated owner of a thriving gambling establishment called El Dorado and the leader of the Barbary Coast, played by Joseph Schildkraut. Upon arriving at El Dorado, Duke meets Flaxen Tarry, a beautiful woman known as the "Flame of Barbary Coast," played by Ann Dvorak, who is engaged to Tito. Flaxen offers to help Duke while playing at the El Dorado, but ultimately Tito cheats Duke out of all his money. Duke then leaves without Flaxen, but returns to San Francisco with another bankroll, accompanied by professional gambler Smooth Wylie, played by William Frawley. Duke beats Tito in a game and wins against other Coast characters, including Horseshoe Brown and Calico Jim. When Calico calls for the help of tough Jot Disko, Tito stops him from killing Duke and instead provokes a gun fight, which Duke wins. Duke then opens a competing gambling establishment, The Silver Dollar, with Flaxen as the star performer. On the opening night, an earthquake strikes during Flaxen's performance and she is injured, but eventually recovers and all ends well.