Stacey Dooley investigates why Peru has taken the title of the world's cocaine capital. Her journey starts in Lima where she meets the Brits locked up in Peru's jails for smuggling cocaine to Europe. Travelling into the countryside she then discovers how alarmingly easy it is for cocaine to be grown and produced here. Stacey joins government forces as they launch a major crackdown in an attempt to destroy this multi-million dollar industry - but will the fightback be enough? Finally she travels deep into the rainforest where farmers are growing a new super strain of coca plant. Able to grow in damp jungle conditions it threatens to open up millions of new acres to coca production and flood the world with even greater quantities of cocaine.

Stacey Dooley investigates the growing drug craze sweeping through Thailand. Yaba, a dangerous mix of methamphetamine and caffeine, has gripped the nation and unleashed a terrifying wave of violence among its users. She uncovers the human cost, visiting a shocking ward full of 'zombie' addicts, many of whom face the risk of long term psychosis, and she also meets users who have started taking the drug as young as 12. Stacey joins the Thai authorities as they try to fight back, joining patrols near the Burmese border and drug raids on Bangkok bars. In Bangkok she discovers that dealers are starting to target western tourists and asks if this dangerous new drug could soon claim its first victims amongst British tourists.

Stacey Dooley travels to Ukraine on Europe's far eastern edge to investigate the struggle to keep drugs out of the UK. Stacey reveals that drug cartels from South America have been using Ukraine as a transit hub to smuggle cocaine into western Europe. To uncover why cocaine shipments are taking this 2,000-mile detour, Stacey visits a new frontline in the war against international drug trafficking - the port of Odessa on Ukraine's Black Sea coast. Ukrainian officials show her the tricks traffickers use to hide drugs within cargoes - inside anything from industrial furnaces to excavated pineapples. But she soon learns from a port worker and a former drug trafficker that Ukrainian customs officials are notoriously open to bribes to get cargoes through. Stacey also discovers that, because the drugs smuggled into Ukraine are too expensive for most local drug users, some are resorting to horrific homemade substitutes. Perhaps the worst is 'crocodile', so called because it rots the flesh of users and turns it scaly. Stacey meets some young addicts as they make a batch from bleach, petrol and tablets bought at the chemist. Learning they have only months to live, Stacey is also shocked to hear that police have recently found 'crocodile' in the UK.