A mysterious prisoner dies while escaping from Fort-L'Évêque prison. Who is he and why keep his name secret? At the same time the King has ordered Nicolas Le Floch to find a precious flute which will supposedly seal the Franco-Austrian alliance and foil the plots being hatched against Queen Marie-Antoinette.
Paris 1777. Nicolas enquête sur la mort d'un prisonnier qui a tenté de s'échapper de la prison de Fort-L'Evêque.
