CineCalidad. While on a ship to Skagway, Alaska, Duke and Chester find a map to a secret gold mine, which had been 'stolen' by thugs. In Alaska to recover her father's map, Sal Van Hoyden falls in with Ace Larson, who secretly wants to steal the gold mine for himself. Duke, Chester, the thugs, Ace and his henchman chase each other all over the countryside—for the map.