The year is 1931. The new and luxurious transatlantic liner Empress of Britain is on her eastward passage. Among the first-class passengers on board are two English confidence tricksters, making a discreet exit from a little awkwardness they have left behind them in the United States. A chance meting on deck brings them a tempting new target in the shape of Miss Charnwood and her niece, the beautiful Diana, only child of the immensely wealthy Fabian Charnwood.