In 1899, the Republic is on the verge of explosion. When the corpse of an unknown woman is found in the Seine, an ambitious young inspector is propelled into the heart of a criminal investigation which will reveal a heavy state secret.

When André Savignac, the mayor of Saint-Guilhem-Le-Désert, is found hanging from the Devil's Bridge, Marina Fazergues comes back to her home village to investigate the mysterious death.