The Citarum river has been called the most polluted waterway on Earth, and this film follows a reporter teaming up with international scientists and the citizen group Green Warriors to find out why. They test water samples, rice paddies, and children's hair along the riverbanks and find toxic chemical residues in a watershed that 14 million Indonesians depend on for drinking, washing, and farming. The investigation traces much of the contamination to roughly 500 textile factories that discharge wastewater straight into the river, supplying garments to international fashion brands, several of which are confronted on camera about their suppliers. The film also tracks the fallout from its own findings: new Indonesian wastewater regulations, a presidential cleanup plan, and promises from clothing companies to tighten oversight. Interviews with villagers, factory workers, and scientists ground the science in daily life along the water, showing rice fields irrigated with dyed runoff and children bathing in water discolored by industrial waste.