The year is 1931. The new and luxurious transatlantic liner Empress of Britain is on her eastward passage. Among the first-class passengers are two English confidence tricksters, making a discreet exit from a little awkwardness they have left behind. A chance meeting on deck brings them a tempting new target in the shape of Miss Charnwood and her niece, the beautiful Diana. It's a trick they've pulled before. Charm the daughter into an engagement to marry, then get the father to buy you off. So confident are they, that they make a pact: whichever of them wins Diana Charnwood's love, will share his fortune with the other. Who would imagine that these smooth operators would let their hearts rule their heads? Or that violent death would find its way into their neat little scheme? Or that they would stumble into something much darker and deeper than either had suspected.