A months-long investigation by Interpol's special services has already revealed the identity of the main trafficker in Paris, a certain Chando and his accomplice Magda. They run a cabaret in Montmartre where the drug is regularly distributed, but the police are still powerless to discover the means used by the traffickers to move opium between Istanbul and the major capitals. A network is organized to follow a certain Madeleine who regularly makes the journey. Her luggage was searched in vain, and the consul, when asked about her, could only praise her: she had long been devoted to repatriating the bodies of her compatriots who had died abroad, free of charge, when the families so wished. On the other hand, the French police are on the trail of Mathias, accused of murdering an old peasant who claimed the inheritance of his son, who died abroad.