A Parisian art dealer is found dead in his hotel room the day after a Paganini concert. In his wallet is a scrap of sheet music, torn from a page that belongs to the competition's winner. But how did the dead man get hold of it? And why? Detective Antonio Guastafeste asks violin maker Gianni Castiglione to help him navigate the curious world of classical musicians, their priceless instruments, and the unsavory dealers who prey upon them.