In the one-hour special, Derren employs his unique combination of skills to investigate the psychology behind gambling, culminating in a huge, one-off bet by a single mum from London employing his 'system' for betting on horse racing. As Derren himself explains: 'I took a member of the public and I told her which horse would win in a certain race; when it did win she was intrigued and I did it again and again and she started to bet more and more money according to my system. 'She's scraped together every last penny she could find and she is risking it all on one final race. Is it really possible to predict every time which horse will win? Welcome to The System.' The show was shot on locations including Sandown Park and Newbury race courses.