‘Basuco’ is now considered the cheapest drug in the world, at 20 cents a hit. It’s made from the residue leftover from cocaine production, mixed with brick dust, volcanic ash, sulphuric acid, kerosene and sometimes ground-up human bones. The high is all-consuming and shockingly addictive, and an epidemic of basuco dependency is tearing through poor communities all across South America. For the cartels, often the cheapest and deadliest drugs are the most profitable. In this episode, we meet the shadowy figures behind this epidemic and visit the neighbourhoods it has destroyed in its wake.