A pioneer of electronic music, Pierre Henry (1927-2017) has, since the 1950s, alongside Pierre Schaeffer, laid the foundations of what characterizes the music of our time. At the time, everything had to be invented: the sounds, the tools to manipulate them, the ways of broadcasting them. He influenced the pop music of the 1960s and 1970s, from the Beatles to Pink Floyd, and up to the DJs of the 1990s. He is the author of an absolute hit: the electronic jerks composed with Michel Colombier for the 'Messe pour present time' created by Maurice Béjart in 1967. But above all he is the creator of a prolific work, from the end of the 1940s to the 2010s, where pure and incredible sound experiences coexist with musical settings of texts to constitute mock operas of a new genre. Thanks to often unpublished documents, this documentary invites us to listen to Pierre Henry tell us about his journey and above all to listen to his music, one of the most innovative of the 20th century.