In a London basement in the late 1960s, a handful of engineers and composers built some of the first synthesizers in Britain, years before the technology reached rock bands or pop charts. The film centers on Peter Zinovieff and the company he founded, Electronic Music Studios, whose EMS synthesizers and the peculiar minds behind them shaped sounds that would later turn up everywhere from Pink Floyd to the BBC Radiophonic Workshop. Interviews with the surviving engineers and musicians who worked in that basement studio trace how homemade circuitry and tape experiments turned into commercial instruments, and how a small group of obsessives ended up rewiring what music could sound like. Archival photographs and recordings sit alongside present-day recollections, filling in a period of British music history that rarely gets attention next to the more famous American synthesizer pioneers. The story stays focused on invention rather than fame, following the actual machines and the arguments over how to build them, and ends with a clear line from that basement to the electronic music heard everywhere now.