Murder on the Mauretania - Conrad Allen

Only a few short months after crossing the Atlantic aboard the Lusitania, George Porter Dillman and Genevieve Masefield are back in Liverpool to embark on the first voyage of the Mauretania. Again working undercover as private detectives, the two mingle effortlessly among the ship's other passengers. Soon after it leaves port, one of the passengers vanishes, complicating already unpleasant circumstances. At first believing that the man was simply swept overboard in a storm, Dillman and Genevieve soon come to realise that his disappearance is an act of murder.