When they sail from New York on the Celtic, a White Star ship, George Dillman and Genevieve Masefield are warned that a dangerous criminal may be aboard. Genevieve excites the interest of two passengers, a Briton and an American, who compete for her attention. Also on board is the creator of the most famous fictional detective of them all - Sherlock Holmes.
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.
Genevieve Masefield & George Porter Dillman find unusual travelers on the Salsette: two British men, traveling independently, who clearly dislike each other; an elderly Indian man whose powers of deduction may be based on more earthly techniques than his claimed mystical energy; and a young woman & her get involved in every bit of trouble aboard the Salsette - including murder!
George Porter Dillman and Genevieve Masefield, new to the P&O shipping line, their new employers, are at first disappointed with the Marmora. When a dead body turns up, however, George and Genevieve know they've got their work cut out for them. Suspects abound, and on such a small ship keeping the demise of the poor victim a secret is proving tougher than they'd like.
As Genevieve Masefield and George Porter Dillman prepare to embark on another Atlantic crossing aboard the Caronia, they encounter two men brandishing shotguns, herding a man and a woman aboard ship in shackles.
Curious, the two detectives find that the young couple have been captured in New York by Scotland Yard and are being transported back to England to stand trial for murder.
George Porter Dillman and Genevieve Masefield temporarily join the Minnesota, a combination freighter and passenger ship owned by the Great Northern Steamship Company, as private detectives. After a fiery Catholic missionary is murdered in what proves to be the first in a series of crimes that will stretch them to their limit. Dillman and Genevieve have to use all their skills to combat danger.
Posing as passengers on the maiden voyage of the Mauretania, George Porter Dillman and Genevieve Masefield endure a nightmare voyage. 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. The presence of 12 tons of gold bullion on board convince Dillman and Genevieve of premeditated murder...
1907: George Porter Dillman sets sail from Liverpool on the Lusitania's maiden voyage. Hired to pose as a passenger, George is in fact a private detective for the Cunard Line. When an expensive piece of jewelry is reported stolen and a body is found, George works quickly to solve both crimes, makes an unusual friend, Genevieve Masefield, and uncovers secrets aboard the ship that prove explosive.