Who do you think of when you think about an opiate dealer? Probably not a young woman in China, who dreamed of being an English teacher. This is the story of one woman in her 20s who’s made a career out of sending fentanyl through the post. The BBC’s Danny Vincent takes us to meet the new generation of drug kingpins, who Jeremy Douglas from the UN says are disrupting the drugs market just like Uber did for transport.

Producers: Heidi Pett, Lucy Hancock, Georgia Coan and Jaja Muhammad