Every year, 1000 homicides are committed in France. In 80% of the cases, the author is apprehended. But 200 murders remain unsolved... Arnaud Poivre d'Arvor, surrounded by Jean-Marc Bloch, a great criminal investigator, and Negar Haeri, a young criminal lawyer, look back at 11 cases that have seen progress, elucidations, resolutions... Among them, the case of little Grégory, the Chevaline massacre or the Dupont de Ligonnès case. Together, they shed new light and offer an update on the criminal stories that have fascinated France.