A fifth of the world’s cocaine is produced in one valley. Controlled in part by Shining Path Maoist guerillas, Peru’s poorest region, the Valle de los Ríos Apurímac, Ene y Mantaro, is ungovernable and the drug trade flourishes. We gain exclusive access to hear the coca growers, the cocaine cooks in their secret jungle labs, dealers and their ‘mules’ explain the business and we travel to Bolivia, the destination of the cocaine and the police units trying to cope with the influx. [This video was re-captioned and the title amended on 20 April 2017 to clarify that some of the filming took place in Bolivia.]