A gripping docu-thriller about a groundbreaking surveillance programme, and the brilliant mastermind behind it. Cryptologist Bill Binney is a former intelligence official with the United States National Security Agency (NSA). Joining the organisation in 1970, and serving as its Technical Director since 1997, he developed a sophisticated programme named ThinThread for gathering data capable of providing clues – in real-time – of potential terrorist threats. Built-in safeguards would have prevented the massive surveillance methods later exposed by Edward Snowden. So why was this programme killed off by the NSA management? Who was behind that? And could ThinThread have prevented 9/11?