Paris, 1899. The French President Félix Faure has just died. Crippled by far-right and anti-Semitic groups and by the anarchist threat, France has never seemed so weak. While police chief Louis Lépine returns in an attempt to restore public order in Paris, the discovery of a woman's torso propels ambitious young detective Antoine Jouin deep inside police headquarters. The investigation is being closely followed by corrupt officer Joseph Fiersi, who hires a courtesan, Meg Steinheil, as a snitch.