"I wanted to film the sound,” says Bernard Josse of his film portrait on saxophonist Peter Brötzmann. This German musician has been a leading figure of European jazz since his album Machine Gun (1968). Brötzmann shifted the American influence of free jazz towards a high-impact, vociferously energetic type of performance also appreciated by aficionados of punk, noise and style-free experiment. Brötzmann’s volcanic sound is as formidable as ever, even in the artist’s 70th year, when the film was made. Josse notes: "One question became central to the making of this film: how have musicians developed so much energy over the last 50 years? What sustains it? Peter is always seeking, finding, transforming [...] He is never self-satisfied, always exploring new paths. I consider him a true creator.” Various prominent artists perform and speak on camera, such as Evan Parker, Han Bennink and Ken Vandermark.