“Yes, yes!” I cried eagerly.

“I take all such things down on the lift to the vaults at night, sir, under the supervision of the assistant manager—­and I can assure you that nothing of the kind has been left with us to-day.”

I stepped out of the call-box unsteadily.  Indeed, I clutched at the door for support.

“What is the meaning of Si-Fan?” Detective-sergeant Fletcher had asked that morning.  None of us could answer him; none of us knew.  With a haze seeming to dance between my eyes and the active life in the lobby before me, I realized that the Si-Fan—­that unseen, sinister power—­ had reached out and plucked my friend from the very midst of this noisy life about me, into its own mysterious, deathly silence.

CHAPTER VII

CHINATOWN

“It’s no easy matter,” said Inspector Weymouth, “to patrol the vicinity of John Ki’s Joy-Shop without their getting wind of it.  The entrance, as you’ll see, is a long, narrow rat-hole of a street running at right angles to the Thames.  There’s no point, so far as I know, from which the yard can be overlooked; and the back is on a narrow cutting belonging to a disused mill.”

I paid little attention to his words.  Disguised beyond all chance of recognition even by one intimate with my appearance, I was all impatience to set out.  I had taken Smith’s place in the night’s program; for, every possible source of information having been tapped in vain, I now hoped against hope that some clue to the fate of my poor friend might be obtained at the Chinese den which he had designed to visit with Fletcher.

The latter, who presented a strange picture in his make-up as a sort of half-caste sailor, stared doubtfully at the Inspector; then—­

“The River Police cutter,” he said, “can drop down on the tide and lie off under the Surrey bank.  There’s a vacant wharf facing the end of the street and we can slip through and show a light there, to let you know we’ve arrived.  You reply in the same way.  If there’s any trouble, I shall blaze away with this”—­he showed the butt of a Service revolver protruding from his hip pocket—­“and you can be ashore in no time.”

The plan had one thing to commend it, viz., that no one could devise another.  Therefore it was adopted, and five minutes later a taxi-cab swung out of the Yard containing Inspector Weymouth and two ruffianly looking companions—­myself and Fletcher.

Any zest with which, at another time, I might have entered upon such an expedition, was absent now.  I bore with me a gnawing anxiety and sorrow that precluded all conversation on my part, save monosyllabic replies, to questions that I comprehended but vaguely.

At the River Police Depot we found Inspector Ryman, an old acquaintance, awaiting us.  Weymouth had telephoned from Scotland Yard.

“I’ve got a motor-boat at the breakwater,” said Ryman, nodding to Fletcher, and staring hard at me.