The United Nations announced in 2013 that Peru has overtaken Colombia as the world's top producer of coca, the raw plant material used to manufacture cocaine. For the past two decades, Colombia has been virtually synonymous with cocaine. Now that Peru has become the global epicenter of cocaine production, the Andean nation runs the risk of becoming the world's next great narco state.The Peruvian government is trying to crack down on the problem by ramping up eradication of coca plants, and devoting military and police resources to interdiction efforts. Despite the response - and a hefty amount of foreign aid devoted to combatting cocaine production - Peruvian coke is being consumed in the nightclubs of Lima and in cities around the world like never before.VICE News travels to Peru to learn more about the government's battle plan against cocaine, and to see how nearly every aspect of Peruvian society is caught up in the fight. We witness how the fine, white powder has forced an entire nation to the brink in the global war on drugs.In part four of the five-part series, VICE News correspondent Kaj Larsen visits Lima, where he speaks with foreigners who have served time in Peruvian prisons for drug trafficking, now stuck in Peru on parole.