Why does a minor chord sound sad and a major chord sound happy, and why does music move people who have no formal training in it at all? This PBS film, drawn from Philip Ball's research, puts neuroscientists, musicians, and psychologists in conversation to test what happens in the brain when it processes rhythm, pitch, and harmony. Bobby McFerrin demonstrates how audiences instinctively complete a pentatonic scale without being taught it, and researchers scan listeners' brains to show music activating regions tied to memory, movement, and emotion simultaneously rather than one isolated "music center." The film moves between concert halls, labs, and hospital wards, including work with patients whose speech has been restored through musical rhythm after brain injury. Jazz, classical, and pop examples all get used as evidence rather than decoration, and the film keeps returning to one question: whether music is a byproduct of other cognitive skills or a distinct instinct wired into the species. It ends without fully resolving that, but the case studies along the way are concrete enough to make the argument worth following.