George Dillman and Genevieve Masefield have to be on their mettle when the great J.P.Morgan sails to New York with them on the Oceanic, a vessel that belongs to a shipping line Morgan owns. The death of his bodyguard and the theft of priceless paintings from his stateroom throw everything into confusion.

The presence on board of an unwanted suitor for Genevieve, and a mad Welsh artist with his wife and mistress in tow, complicate an already difficult situation. The only way to placate the infuriated J.P.Morgan is to solve the murder but time is limited and there are far too many suspects.