Phoebe Mullins spent years as a peacemaker between her conductor husband and the music world's most petulant stars. But when she lands a job at an aging diva's opera school, she has no idea that her shrewd knack for diplomacy will be tested once again. At the exclusive Long Island opera colony of singing legend Anna Varovna, residents are rehearsing their summer production of Così fan tutte. But Phoebe quickly sees that relations offstage are less than cozy, and Mozart's honeyed melodies soon give way to high-decibel melodrama. Then handsome baritone Frank Palermo is found dead of an allergy to the penicillin pill covertly planted among his vitamins--and Anna urges Phoebe to make some discreet inquiries. Could Frank's recent joining of the Children of Truth cult have somehow earned him an early grave? And why did Frank, clutching his opera score as he died, scratch an X on the name "Amadeus"? Before Phoebe can make sense of it all, a fatal cacophony of love, lust, genius, and guilt reveals itself--and the tempo accelerates as death strikes again.