She glided past him to the door, avoiding his outstretched arm with an artless art which made me writhe; for once I had been the willing victim of all these wiles.

“But—­” began Slattin.

“I will ring you up in less than half an hour,” said Karamaneh and without further ceremony, she opened the door.

I still had my eyes glued to the aperture in the blind, when Smith began tugging at my arm.

“Down! you fool!” he hissed harshly—­“if she sees us, all is lost!”

Realizing this, and none too soon, I turned, and rather clumsily followed my friend.  I dislodged a piece of granite in my descent; but, fortunately, Slattin had gone out into the hall and could not well have heard it.

We were crouching around an angle of the house, when a flood of light poured down the steps, and Karamaneh rapidly descended.  I had a glimpse of a dark-faced man who evidently had opened the door for her, then all my thoughts were centered upon that graceful figure receding from me in the direction of the avenue.  She wore a loose cloak, and I saw this fluttering for a moment against the white gate posts; then she was gone.

Yet Smith did not move.  Detaining me with his hand he crouched there against a quick-set hedge; until, from a spot lower down the hill, we heard the start of the cab which had been waiting.  Twenty seconds elapsed, and from some other distant spot a second cab started.

“That’s Weymouth!” snapped Smith.  “With decent luck, we should know Fu-Manchu’s hiding-place before Slattin tells us!”

“But—­”

“Oh! as it happens, he’s apparently playing the game.”—­In the half-light, Smith stared at me significantly—­“Which makes it all the more important,” he concluded, “that we should not rely upon his aid!”

Those grim words were prophetic.

My companion made no attempt to communicate with the detective (or detectives) who shared our vigil; we took up a position close under the lighted study window and waited—­waited.

Once, a taxi-cab labored hideously up the steep gradient of the avenue . . .  It was gone.  The lights at the upper windows above us became extinguished.  A policeman tramped past the gateway, casually flashing his lamp in at the opening.  One by one the illuminated windows in other houses visible to us became dull; then lived again as mirrors for the pallid moon.  In the silence, words spoken within the study were clearly audible; and we heard someone—­presumably the man who had opened the door—­inquire if his services would be wanted again that night.

Smith inclined his head and hung over me in a tense attitude, in order to catch Slattin’s reply.

“Yes, Burke,” it came—­“I want you to sit up until I return; I shall be going out shortly.”

Evidently the man withdrew at that; for a complete silence followed which prevailed for fully half an hour.  I sought cautiously to move my cramped limbs, unlike Smith, who seeming to have sinews of piano-wire, crouched beside me immovable, untiringly.  Then loud upon the stillness, broke the strident note of the telephone bell.