A million dollars’ worth of gold bullion has been stolen from the Wakefield Mint under strange circumstances. Mr. hardy is asked to investigate but before long his life is threatened, and he asks Frank and Joe to help him. The boys fly to Zurich, Switzerland, hoping to get information at the Swiss Gold Syndicate and to find the man who has stolen a valuable ancient gold figurine from a New York museum. Their search on both counts seems futile as they return to the United States where they uncover clues that lead them to an adventure in the Yucatán jungle. But the Hardy’s travels lead to nothing but new doubts and nagging suspicions. And now their lives are in danger.
Franklin W. Dixon is a pen name used by a variety of authors writing for the classic series, The Hardy Boys. The first and most well-known "Franklin W. Dixon" was Leslie McFarlane, a Canadian author who contributed 19 of the first 25 books in the series. Other writers who have adopted the pseudonym include Christopher Lampton, John Button, Amy McFarlane, and Harriet Stratemeyer Adams.