A mysterious explosion erupts in the northern Italian town of Seveso at its Icmesa factory in 1976. Hidden from the public, the story leaks as the impact of poisonous dioxin from its reactor exposes children to chemical burns, 77,000 animals die and the environment is radically transformed - resulting in a mass evacuation. At the heart of the storm is Jorg Sambeth, the technical director of Givaudon which is responsible for Icmesa, a company belonging to the Swiss Hoffmann La-Roche pharmaceutical conglomerate. Not a simple story the film questions who bears the ultimate responsibility. What was really being produced at Icmesa? For whom? And, how does a transnational corporation protect its interests? These are all part of the fascinating puzzle revealed in this riveting, troubling documentary.