In the vicinity of the Franco-German border, within the core of the Black Forest and the binational military base, a mass grave is uncovered. The grave contains the remains of 12 men, hailing from both French and German origins.

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.