October 16th, 1984: Gregory, a 4 year old boy goes missing. Hours later, he's found dead in the Vologne River, wrists and ankles bound. This true crime drama series focuses on the events and the human tragedy surrounding the death of Gregory - a momentous unresolved investigation that marked a turning point in the media and judicial system in France.

Saïd heads BRI, an elite task force of young police officers dealing with organised crime. As the new chief, Saïd tries to find his place in the team while trying to stop an all-out gang war from breaking out in Paris.