When Peru’s President Martín Vizcarra came to power in 2018, one of his first priorities was to gain control over the devastating outbreak of illegal gold mining operations. In February 2019, the government launched Operation Mercury, a decisive action to shut down an entire town built around an illegal gold mine. This episode follows chief environmental prosecutor Karina Garay as she works with the police, army and navy in destroying illegal mines and arresting miners in protected areas, while retraining illegal miners and persuading them to join the formalized mining operations.