Every city has a drug scene. But when big holiday events happen, drug dealers have to work overtime. Whether it's a coke-fuelled Spring Break in Florida, a heroin odyssey on New Year’s Eve in New York, or a Mardi Gras Molly-fest, the heat is on: out-of-town rivals, dealers selling fake product – and the cops on high alert. Meanwhile five shows chase the product from origin to sale. Featuring extreme access filming in Peru, in Mexico, and in the former Soviet Union we chart the supply chains of the world’s most dangerous drugs, their economic and health impact – and what law enforcement is doing to stop them.