Dead, Mr. Mozart

Caroline, wife of England's King George IV, is being investigated for her ``adultery--and hence her treason.'' Wolfgang Gottlieb Mozart, still alive in London in 1820 in this alternative history, has been reduced to composing ``curtain-raisers,'' supplementing his meager income by occasional service to the gentry. A bright spot enters the composer's life when Lord Hertford, an opera patron, persuades the theater to hire his protege, young soprano Betty Ackroyd. Upon learning the theater is involved in dangerous schemes touching on the royal squabbles, further complicated when a corpse is found in Ackroyd's dressing room, Mozart uneasily undertakes some quiet snooping. Bastable (To Die Like a Gentleman) keeps things moving, but, criminal acts and scandalous behavior notwithstanding, this is more curtain-raiser than grand opera. (Apr.)