Wendy Bendel's partner killed himself after struggling with a 20-year gambling addiction. In a confession he wrote for Wendy, he singled out the high-stakes, high-frequency fixed-odds betting terminals (FOBTs) found in bookmakers across the UK.

Wendy embarks on a journey to find out what it is about the design of the machines that makes them so addictive and sees evidence that they can affect the brains of long-term gamblers. She discovers the billions they generate has divided the industry, with former insiders now accusing the bookies of putting profits before people.