When Ketty Hjøllund loses her husband Thorkild to the deadly neurological disease ALS, she discovers that she is not alone. Several suspicious cases of illness pop up in the central Jutland town of Grindsted, home to one of Denmark's biggest pollution scandals. Ketty suspects a link between Thorkild's death and the pollution and starts her own investigation. While she finds several new cases, the authorities mistakenly conclude that living in the town does not make people sick, and the town's residents ask Ketty to keep quiet. But Ketty does not give up until she is certain that the pollution is responsible for her husband's death.