At the beginning of the 70s of the XX century appeared in music stores a disc with the title "Music of the lute of the XV-XVII centuries". It met with truly phenomenal success and was found in virtually every Soviet family. The first piece was a work "Canzone" by the composer Francesco da Milano (1497-1543). On the melody of the "Canzone" the poet Henri Volokhonski composed the poem "Under the blue sky" using biblical images taken from the Old Testament of the prophet Ezekiel. The song "Under the Blue Sky" became a well-known ballad and the aria "Ave Maria" a worldwide hit. And suddenly, twenty years later, it turned out that none of the Italian composers listed on the cover had composed this type of work and that their author was the hero of our film, the autodidact Vladimir Vavilov. In the film, violinist Andrei "Ryusha" Reshetin, a specialist in Russian music and the language of the Baroque period, talks about the secrets of music.