Darren uncovers why Scotland has the highest drug-related death rate in Europe.He begins his journey on the front line of the drug crisis by spending a shift with the ambulance service during a busy Friday evening in Glasgow. He then travels to Fife, where he is trained to use Naloxone, a life-saving treatment that reverses the effects of an opioid overdose, and meets Reece who has been saved by the treatment twice.Darren revisitis his time in rehab in 2018, returning to talk with the therapist who aided his recovery, before visiting neuroscientist Dr Lucy Troup to learn exactly what happens inside the brain when drugs are taken. Historian Dr Jim Mills walks him through a potted history of drugs in Scotland since 1575 and shines a light on how drug addiction evolved from a medical issue to a criminal one.In Govan, Darren meets former police officer Simon Maclean, who, after years working undercover as a drug dealer, now thinks a radical overhaul of Scotland's drugs laws is needed. Taking a trip inside Barlinnie Prison, Darren meets some of the prisoners to learn about the role addiction plays in so many crimes, and how our current system fails to address this.Darren then spends a day at the Simon Community Access Hub where he meets former heroin users Kevin and Alex, who explain how the charity helped their recovery. He also meets Jim, a former heroin user who became a staff member at the hub and who now uses a revolutionary scanner to show intravenous drug users how to safely inject drugs and where to seek support.Darren then meets Dr Saket Priyadarshi, the clinical lead for Glasgow's alcohol and drug recovery services, to find out why there are so many methadone users in Scotland and what the alternatives are, before heading to the banks of the River Ayr to discover a rehab model that is changing the recovery landscape.