A panel of scientists, led by the kind of research that produced Professor David Nutt's controversial 2007 Lancet rankings, spends two years scoring twenty of Britain's most commonly used drugs against a single scale of harm. The film walks through the criteria used to build that scale: physical damage to the user, potential for addiction, and the wider damage a drug does to families, crime rates, and health services. Heroin, crack cocaine, and alcohol land at the sharp end of the list, while drugs long treated as harmless by comparison, including cannabis and ecstasy, get reassessed against the same numbers. Interviews with the researchers explain why legal status and public perception often diverge sharply from the measured harm, and the ranking method itself becomes as much the subject as the drugs it scores. The result is less a scare campaign than an argument for rethinking how a society decides which substances to fear most.