A genius painting by Leonardo da Vinci— the famous “Madonna Litta”—has disappeared from the Hermitage in St. Petersburg. In the frame, the thief left another portrait—indistinguishably similar to the Madonna Litta… if not for the horrifying small monster depicted in place of the divine baby. Restoration expert Dmitry Starygin, who sincerely reveres the work of the Italian master, is unfairly suspected of the theft. Yet the fate of the painting troubles him no less than his own fate, and Dmitry flees to Rome. It was there, before his death, that Professor Arseny Magnitsky worked—leaving behind a diary with a clue about who and for what purpose the beautiful Madonna was needed.