A woman in an elegant, flame-colored opera cloak was crossing the floor and coming in the direction of the spot where we were concealed. She wore a soft silk scarf about her head, a fold partly draped across her face. A momentary view I had of her--and wildly incongruous she looked in that place--and she had disappeared from sight, having approached someone invisible who sat upon the divan immediately beneath our point of vantage. From the way in which the company gazed towards her, I divined that she was no habitue of the place, but that her presence there was as greatly surprising to those in the room as it was to me. Whom could she be, this elegant lady who visited such a haunt--who, it would seem, was so anxious to disguise her identity, but who was dressed for a society function rather than for a midnight expedition of so unusual a character? I began a whispered question, but Smith tugged at my arm to silence me. His excitement was intense. Had his keener powers enabled him to recognize the unknown? A faint but most peculiar perfume stole to my nostrils, a perfume which seemed to contain the very soul of Eastern mystery. Only one woman known to me used that perfume--Karamaneh. Then it was she! At last my friend's vigilance had been rewarded. Eagerly I bent forward. Smith literally quivered in anticipation of a discovery. Again the strange perfume was wafted to our hiding-place; and, glancing neither to right nor left, I saw Karamaneh--for that it was she I no longer doubted--recross the room and disappear. "The man she spoke to," hissed Smith. "We must see him! We must have him!" He pulled the mat aside and stepped out into the anteroom. It was empty. Down the passage he led, and we were almost come to the door of the big room when it was thrown open and a man came rapidly out, opened the street door before Smith could reach him, and was gone, slamming it fast. I can swear that we were not four seconds behind him, but when we gained the street it was empty. Our quarry had disappeared as if by magic. A big car was just turning the corner towards Leicester Square. "That is the girl," rapped Smith; "but where in Heaven's name is the man to whom she brought the message? I would give a hundred pounds to know what business is afoot. To think that we have had such an opportunity and have thrown it away!" Angry and nonplused he stood at the corner, looking in the direction of the crowded thoroughfare into which the car had been driven, tugging at the lobe of his ear, as was his habit in such moments of perplexity, and sharply clicking his teeth together. I, too, was very thoughtful. Clews were few enough in those days of our war with that giant antagonist. The mere thought that our trifling error of judgment tonight in tarrying a moment too long might mean the victory of Fu-Manchu, might mean the turning of the balance which a wise providence had adjusted between the white and yellow races, was appalling.