Composer Stephen Sondheim and actor Anthony Perkins wrote this witty, complex thriller directed by Herbert Ross. A movie kingpin , whose wife Sheila was killed by a hit-and-run driver a year before, hosts a cruise aboard his sleek yacht. His guests are all friends who may know more about Sheila's death than they're letting on. An elaborate murder game with Mediterranean ports-of-call is the itinerary. What unfolds is a mystery so intriguing, so cleverly plotted, even the title is a clue!