The Devil in Music (Julian Kestrel Mysteries #4)
Kate Ross

Traveling on the Continent with his ex-pickpocket valet, Kestrel finds himself caught up in the mysterious and murderous world of the opera. Four years ago, the Italian marquis Ludovico Malvezzi was murdered, and Orfeo, the young English tenor he had been training for a career on the glittering operatic stage, disappeared. As Kestral is irresistibly drawn into the baffling case, he encounters suspects at every turn: a runaway wife and her male soprano lover; a liberal nobleman at odds with Italy's Austrian overlords; a mocking Frenchman with perfect pitch; a beautiful, clever widow who haunts Kestrel's dreams; and the missing Orfeo, the penniless protege who just might be a political agent. And when the killer strikes again, Kestrel's quest for answers spirals into a crescendo of passion, danger, and music as he risks becoming a ruthless murderer's next victim.