Farmer Michel Villeneuve is diagnosed with leukemia after collapsing in his field he’d just sprayed with a weed killer made by the agrochemical giant Saskia. His childhood friend Guillaume Delpierre, a principled politician, crusades to ban the pesticide with the help of his ambitious assistant, Romain Corso. They have to face Mathieu Bowman, a formidable lobbyist hired by Saskia. But when Saskia’s Head of Marketing is found floating in the Seine, his daughter Chloé launches a behind-the-scenes investigation with help from former journalist Claire Lansel, recently hired by Bowman.