Paris, 1899. President Félix Faure has just died in the arms of his mistress, Marguerite Steinheil (Meg). With the Republic on the verge of explosion, Prefect Lépine is called back to business. At the same time, at the prefecture, Inspector Jouin was mobilised for a major investigation to identify "the unknown woman in the suitcase" whose body was recovered from the Seine.