It’s the most exciting concert Cremona has seen in years: a brilliant young Russian playing a violin once owned by the 19th-century master Nicolo Paganini. But the performance is overshadowed by the murder of one of its sponsors. Solving the murder will require a journey into musical history; to make that journey, Cremona’s police-chief will need the help of Gianni Castiglione, an elderly charmer and only mildly larcenous expert in violins.