Gregory Crowne, the ex–crown prince of Hirtenstein, is entangled in yet another murder investigation when a beautiful young Polish countess, Marzelina Zalfeda, is found dead in the Museum of Musical Heritage. Marzelina had come to England to purchase an unknown manuscript by Chopin for her employer, Madame Estelle Wiaroz, but neither the manuscript nor Madame Wiaroz's money can now be found.