Even in the twelfth century, when the wild Mongols broke loose and nearly overran the world, the Tibet infantry under Genghis, the Tchortcha horsemen drafted out of Black China, and a great cloud of Mongol cavalry under the Prince of the Vanguard commanding half a hundred Hezars, never penetrated that grisly and unknown waste. The “Eight Towers of the Assassins” guarded it—still guard it, possibly. The vice-regent of Erlik, Prince of Darkness, dwelt within this unknown land. And dwells there still, perhaps. In front of this wall-map stood Tressa Norne. Behind her, facing the map, four men were seated—three of them under thirty. These three were volunteers in the service of the United States Government—men of independent means, of position, who had volunteered for military duty at the outbreak of the great war. However, they had been assigned by the Government to a very different sort of duty no less exciting than service on the fighting line, but far less conspicuous, for they had been drafted into the United States Department of Justice. The names of these three were Victor Cleves, a professor of ornithology at Harvard University before the war; Alexander Selden, junior partner in the banking firm of Milwyn, Selden, and Co., and James Benton, a New York architect. The fourth man’s name was John Recklow. He might have been over fifty, or under. He was well-built, in a square, athletic way, clear-skinned and ruddy, grey-eyed, quiet in voice and manner. His hair and moustache had turned silvery. He had been employed by the Government for many years. He seemed to be enormously interested in what Miss Norne was saying. Also he was the only man who interrupted her narrative to ask questions. And his questions revealed a knowledge which was making the girl more sensitive and uneasy every moment. Finally, when she spoke of the Scarlet Desert, he asked if the Scarlet Lake were there and if the Xin was still supposed to inhabit its vermilion depths. And at that she turned and looked at him, her forefinger still resting on the map. “Where have you ever heard of the Scarlet Lake and the Xin?” she asked as though frightened. Recklow said quietly that as a boy he had served under Gordon and Sir Robert. “If, as a boy, you served under Chinese Gordon, you already know much of what I have told you, Mr. Recklow. Is it not true?” she demanded nervously. “That makes no difference,” he replied with a smile. “It is all very new to these three young gentlemen. And as for myself, I am checking up what you say and comparing it with what I heard many, many years ago when my comrade Barres and I were in Yian.” “Did you really know Sir Robert Hart?” “Yes.” “Then why do you not explain to these gentlemen?”