1900: In 1899, the Republic is on the verge of explosion. The corpse of an unknown woman found in the Seine will propel an ambitious young inspector into the heart of a criminal investigation which will reveal a heavy state secret.

1905: When the Paris police's vice squad - on the orders of Police Chief Lépine - begin to clean prostitutes off the city's streets, a man's body is found in the Bois de Boulogne. Inspector Antoine Jouin is entrusted with the investigation.