Stacey Dooley returns with another hard-hitting series lifting the lid on the global war on drugs. Heading to remote and hostile regions, she investigates who's really winning this cat-and-mouse battle between the drug cartels and the police. Along the way she reveals the impact that the west's insatiable desire for more potent drugs is having on the people caught in the crossfire. To begin, Stacey is on the trail of the world's most addictive and dangerous drug. Her journey takes her to Mexico, now the world's largest producer of meth, where she discovers that the battle between the cartels, the police and vigilante groups is threatening to overwhelm the very fabric of the state. She joins the army as they track down and destroy the meth super-labs that are now appearing across the country. But she learns that as soon as one lab is dismantled, others replace it. She tracks down hit men and traffickers who work for the cartels and hears shocking stories of violence from the families of their victims. It becomes clear that the power of the cartels now reaches into every corner of Mexican life and the authorities are increasingly powerless to stop it. Stacey discovers that in some places local people have become so desperate that they are taking the law into their own hands and setting up their own vigilante groups to try and fight off the cartels. With heavily-armed police, cartels and now vigilantes all squaring up against each other, Stacey reveals a country in danger of descending into chaos and disorder.

Stacey Dooley investigates a stag's last night of freedom in Prague, a no-holds-barred city that caters for a man's every whim. She meets some of the thousands of girls who are paid to entertain Prague's male visitors and reveals how they really feel about their work. She discovers how the city is littered with brothels thinly disguised as massage parlours and gentleman's clubs, and reveals how the tough competition is putting pressure on the girls to go further and further. Stacey joins the police on patrol to see the daily struggles they face to protect the tourists and mop up the trouble they cause. She also uncovers how the large groups of drunken men become easy prey to Prague's criminals, which the police are struggling to stop. Through unprecedented access, Stacey uncovers the darker side of Prague.

Stacey Dooley travels to Sunny Beach in Bulgaria, which is fast overtaking Magaluf and Kavos as the favourite party destination for young Brits. Stacey uncovers the consequences of a no-rules party scene, where alcohol has the lowest prices in Europe and bar crawls of up to 400 people dominate the strip. She sees what the young Bulgarians working on the resort really think of the British drinking culture and reveals some of the devastating consequences when things go too far. Stacey investigates the easy access British tourists may have to illegal drugs and questions what the authorities are doing about it. In one of the poorest countries in Europe, Stacey visits a part of Sunny Beach many of the tourists don't get to see and spends time with some of the Roma Gypsy community who are blamed for much of the crime on the resort.

Stacey Dooley visits Kenya, were she see's how little of tourists money actually goes to the local people. After spending some time in an all inclusive hotel, she heads down the road and joins in a protest against a current expansion which will see the locals cut off from their only water supply. She meets with the Kenyan minister of tourism to find out what he has to say on the issues.

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.

In Kathmandu, Stacey Dooley continues her investigation into child labour. As the government promises to crack down on the issue in India, Stacey sees how children are crossing the border, to Nepal to work in the embroidery and carpet factories. She manages to help a boy been beaten by his boss be free-ed and meets up with children been sold into slavery by their families. She meets a girl who with the help from a charity was freed from slavery, and goes along to help free her sister.

Stacey investigates the problem of the sexualisation of children in Japan.

Stacey Dooley travels across Canada to investigate what factors led to the disappearance and murders of 1,200 Native American girls and women.

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.

In Nepal, Stacey Dooley investigates why tens of thousands of children under 10 are been forced into working in factories or in domestic slavery. She see's if she can make any difference.

With the UN and FBI suspecting that there are up to 750,000 people online at any one time hunting for children to exploit, how can the booming cybersex trade be policed effectively? Kicking off BBC Three’s Gender Season, Stacey Dooley presents the first of two hard-hitting films from some of the worst places in the world to be female. She investigates why some young women today live in such dangerous, desperate and degrading conditions. In this episode Stacey travels to the Philippines - fast becoming the world capital of the cybersex industry. Here, girls who are rarely let out and often underage must perform on webcams and be photographed for a global online audience. Within the last year alone, 139 Brits were investigated for paying to watch Philippine children being abused. Stacey learns how poverty combined with cheap internet access has led to an increasing number of girls being exposed to online sexual abuse. Discovering the harrowing truth behind this widespread exploitation, Stacey then exposes an even darker side - cybersex dens. We see Stacey at her best as she goes undercover for the first time and follows the police on a major sting, bringing her face-to-face with the criminals behind this new and disturbing phenomenon. She also travels north of Manila and learns that efforts are being made to help some of the 100,000 victims of exploitation, using therapy and counselling from psychologists - some of whom have suffered the same abuse as the children they are helping. Stacey is overwhelmed at the sheer scale of this billion dollar industry, but remains hopeful that if police forces across the world work together, there's a chance this secretive trade can be tackled.