France, 1890s. French intelligence officer Captain Alfred Dreyfus is declared a particularly dangerous criminal, subjected to civil execution and exiled to a tropical island in the Atlantic Ocean. The official charge is spying for Germany. Georges Picard, Dreyfus's former mentor and then the head of one of the departments of the intelligence department, is conducting his own investigation into this controversial case, which is also openly colored in nationalist tones. The main incriminating material against Dreyfus is a mysterious "secret folder" supposedly containing all the necessary evidence. This is what Picard needs to find in order to show the world the innocence of his charge.