Ikonnikov and Polyakov used to be friends many years ago. They were very talented violin players. But after Polyakov got the first place, Ikonnikov radically changed his occupation. Now he is a respected professor. But his apartment was robbed, and the robbers took the most valuable things, including a famous Stradivari’s violin. And now this theft is being investigated. But it is the only one plot line, and there is another one, which is devoted to Antonio Stradivari and his art work.