In 1976, an explosion at a chemical plant near the small northern Italian town of Seveso covers the area in a strange white powder containing deadly dioxins. Eleven-year-old Giuliana "Giulia" Bianchi has lived a carefree life until then. Panic spreads as animals die and residents fall ill with alarming symptoms, while the company running the plant keeps quiet about what happened. Giulia and her friends decide to search for answers themselves, and together with the Japanese journalist Shirou Andou they set out to uncover the truth and make the company answer for the disaster. The drama film draws on a real accident that took place in Italy that year.