Kapellmeister Joseph Haydn would like nothing better than to show his principal violinist, Bartó Daboczi, the door. But with the Empress Maria Theresa’s visit scheduled in three weeks, Haydn can ill-afford to lose his surly virtuoso. But when Bartó disappears—along with all the music composed for the imperial visit—the Kapellmeister is forced to don the role of Kapell-detective, or risk losing his job. Before long Haydn's search uncovers pieces of a disturbing puzzle. Bartó, it appears, is more than just a petty thief—and more dangerous. And what seemed like a minor musical mishap could modulate into a major political catastrophe unless Haydn can find his missing virtuoso.