Regina Clausen is forty-three, successful in her career but insecure and unfulfilled in her personal life. Travelling alone on the luxury liner Gabrielle, she disembarks in Hong Kong saying she will rejoin the ship when it docks in Japan. She is never seen again. Three years later, an anonymous caller to psychologist Susan Chandler's radio show tells of a strange encounter with a man on a cruise ship, and his sinister gift of a ring engraved: 'You Belong To Me'. Susan thinks little of it at the time. But when Regina's mother appears at her office with a ring bearing the same inscription, found amongst her daughter's belongings, Susan begins to suspect that they are on the trail of something menacing and dangerous. As she looks deeper, Susan finds herself confronted with the horrifying possibility that she may know the killer, and that she may even be his next victim ...