November 1907. Only a few short months after crossing the Atlantic aboard the Lusitania, George Porter Dillman and Genevieve Masefield sail from Liverpool on the maiden voyage of the Mauretania. Posing as passengers, Dillman and Genevieve endure a nightmare voyage during which severe weather batters the vessel unmercifully and keeps the passengers away from the decks. Dillman is instrumental in rescuing a crew member from being washed overboard but he is too late to save one of the First Class passengers from the same fate. At first, it looks like a case of death by misadventure. But Dillman and Genevieve come to realize that it was an act of calculated murder, connected with the presence on board of a record shipment of gold bullion - twelve tons in all - sent from the Bank of England.