Messages encoded in the form of musical notes have been sent to Earth for over a thousand years. Dmitro, a programmer, is developing a unique computer programme called ‘Convergencia’, which is capable of deciphering this code. Dmytro calls the code ‘Guido’ in honour of the Benedictine monk Guido d’Arezzo, author of the ‘Hymn to St John’, in which the names of musical notes first appeared. It turns out that all music created by the geniuses of humanity throughout the ages and across all nations contains ciphers sent from outer space. Who is sending them? Why? And most importantly — to whom?