The unidentified body of a homeless man was found on a dune of the Somme. Fatally shot shotgun ... shot in the back. Pure accident? Homicide concealed? Intentional killing otherwise called "murder"? The local Gendarmerie Brigade is in charge of the case, under the direction of the Substitute Aurore Debac. To investigate the death of Vagabond of the Somme Bay, Dawn relies on the persistence of Staff of the Gendarmerie, non-standard methods, BEAUJOUR Paul, newly arrived, who knows nothing about codes region ..