Deep in the heart of the Moselle, in the Uckange furnace Park, is a crime scene as spectacular as it is baffling. The victim is the former Director of the site. When the relentless but sensitive Clément Leroy, captain of the criminal section of the Metz gendarmerie, sets out to investigate, he reconnects with his childhood love, Laure Thouvenin, the victim's daughter and a specialist in industrial history. As this free and unconventional woman becomes increasingly involved in the case, she and Leroy unravel the shocking story of their respective families running over three generations.