On his yacht, The Sheila, named after his deceased wife, movie mogul James Coburn devises a week-long "fishing trip" to flush out her killer among his Hollywood cronies; the catch is largely red herrings, and that's the fun of this fiendishly clever puzzle-on-film, a classic in the viewer-as-detective mode. The suspects include (in addition to Coburn himself) a down-and-out director (James Mason), an aggressive agent (Dyan Cannon), a movie queen (Raquel Welch) and her designing husband (Ian McShane), a struggling screenwriter (Richard Benjamin)-an array straight out of Mankiewicz or Grand Hotel. Stephen Sondheim and Anthony Perkins wrote the script in smart-aleck Hollywoodese ("My mouth is so dry they could shoot Lawrence of Arabia in it"; "I hate my luggage more than life itself")-the kind of chatter that reveals its own miseries and vulnerabilities. Indeed, all the guests have guilty secrets, which Coburn uses as markers in an elaborate game. If you blink you may miss an embedded clue, but sleuth away, do...and good luck.