Fleeing the humiliating arrest of her husband-to-be on the eve of their wedding, Celia Kilbride, a gems and jewellery expert, hopes to escape from public attention by lecturing on a brand-new cruise ship, the Queen Charlotte.<br/>On board she meets eighty-six-year-old Lady Emily Haywood - the owner of a priceless emerald necklace that she intends to leave to a museum after the cruise.<br/>But three days out to sea Lady Emily is found dead - with the necklace missing. And the list of suspects is large and growing.<br/>Celia sets out to find the killer, not realizing that she has put herself in mortal danger before the ship reaches its final destination.