To outward seeming Armand Hecq was a prosperous Parisian financial agent, whose offices in the Boulevard des Capucines, opposite the Grand Hotel, were visited by all sorts of persons of both sexes. None, excepting those "in the know," suspected that these handsome offices, with the white-headed old _concierge_ wearing the ribbon of 1870, were in reality no mere financial establishment, but the headquarters of the international espionage of the Allies. None realised that the crowds of "speculators," who flocked thither in the pursuit of ever-elusive wealth, included among them dozens of men and women who day by day carried their lives in their hands in their never-ending warfare with the unscrupulous and resourceful agents of Germany. None dreamed that to the busy staff finance was a mere side-line; that their real interest was not the daily fluctuations of the Bourse, but the thread of Hun intrigue which ran through all the crowded life of the gay city, and was nowhere stronger than in the department of finance. "Now, Sant," said Hecq abruptly, after we had sat silent for a few minutes while I ran over in my mind the essential facts of the new and tangled case. "You have seen the photographs and the _dossier_, and you understand the position. What is your opinion?" "There can be but one," I answered leisurely. "Before the war, Jules Cauvin, of Issoire in Auvergne, was a struggling corn-merchant. He has since, in some unaccountable way, blossomed out into a man of wealth, and has purchased an important estate with money which has come from some mysterious source. Constant payments appear to reach him from a firm of motor-engineers somewhere in England. In his sudden prosperity he has bought a villa at Mentone, where he lives during the winter with his wife and family, and he is often seen at the tables at Monte Carlo. Among those who have stayed with him at the Villa des Fleurs was the Russian Colonel Miassoyedeff, who was recently hanged as a spy of Germany. There can be only one conclusion from all this."