Until these questions were satisfactorily answered, further progress was impossible. Nayland Smith frankly admitted that he was out of his depth. "It looks, on the face of it, more like a case for the Psychical Research people than for a plain Civil Servant, lately of Mandalay," he had said only that morning.

"Sir Lionel Barton really believes that supernatural agencies were brought into operation by the opening of the high priest's coffin. For my part, even if I believed the same, I should still maintain that Dr. Fu-Manchu controlled those manifestations. But reason it out for yourself and see if we arrive at any common center. Don't work so much upon the datum of the green mist, but keep to the FACTS which are established."

I commenced to knock out my pipe in the ash-tray; then paused, pipe in hand. The house was quite still, for my landlady and all the small household were out.

Above the noise of the passing tramcar I thought I had heard the hall door open. In the ensuing silence I sat and listened.

Not a sound. Stay! I slipped my hand into the table drawer, took out my revolver, and stood up.

There WAS a sound. Someone or something was creeping upstairs in the dark!

Familiar with the ghastly media employed by the Chinaman, I was seized with an impulse to leap to the door, shut and lock it. But the rustling sound proceeded, now, from immediately outside my partially opened door. I had not the time to close it; knowing somewhat of the horrors at the command of Fu-Manchu, I had not the courage to open it. My heart leaping wildly, and my eyes upon that bar of darkness with its gruesome potentialities, I waited—waited for whatever was to come. Perhaps twelve seconds passed in silence.

"Who's there?" I cried. "Answer, or I fire!"

"Ah! no," came a soft voice, thrillingly musical. "Put it down—that pistol. Quick! I must speak to you."

The door was pushed open, and there entered a slim figure wrapped in a hooded cloak. My hand fell, and I stood, stricken to silence, looking into the beautiful dark eyes of Dr. Fu-Manchu's messenger—if her own statement could be credited, slave. On two occasions this girl, whose association with the Doctor was one of the most profound mysteries of the case, had risked—I cannot say what; unnameable punishment, perhaps—to save me from death; in both cases from a terrible death. For what was she come now?