On September 5, 2012, in a parking lot on a forest road in the Alps, a few kilometers from the village of Chevaline, an English family and a French cyclist were found dead, brutally shot. A little girl survived the tragedy and was rushed to the hospital: the killer had left her for dead after striking her on the head. The gendarmerie secured the crime scene and began a meticulous investigation to find any traces the killer might have left behind. A phone call from the owner of the campsite where the English family was staying would change everything.