Three top-flight N.Y. musicians--a violinist, a cellist, a flautist--are found shot to death, together, in a walkway behind the Metropolitan Opera. The only clues: the fact that all three had mysterious plans for the week of November 4; and that one of the musicians wrote ""Beethoven?"" across that week in her calendar. So weary cop Richard Marritt is stuck--until routine interviews with all the other first-rate pickup musicians in town lead to lovely violist Judith Dart: she confesses that a stranger named Klaus Ehrlich has paid her $10,000 to learn the viola part in a mysterious symphony. . . to be performed somewhere in Europe the week of November 4th! Were the dead musicians similarly hired, then killed because they figured out that the music is Beethoven's unknown 10th Symphony? And is ""Klaus Ehrlich"" really Beethoven expert Karl Heiden--henchman to Austrian millionaire Victor Pesage, a madman with a Beethoven complex? So it seems. Off to Vienna go Richard and Judith, then, determined to foil Pesage's scheme--which involves the private performance of the mystery-symphony and the probable murder of all those hired musicians. And along the way low-brow Richard, who's been getting a primer-education in Beethoven's life-and-work, falls hard for high-brow Judith (he's half-happily married) but ultimately resists adulterous temptation. Too unsophisticated for most music-lovers, too comic-book-silly for suspense--but a likable doe-dad nonetheless, cheerfully padded with a few lessons from Music Appreciation 101.