Beneath the
make-up with which I had stained my skin, I knew that I had grown
more than a little pale.

"Fletcher!" I whispered, "we are on the eve of a great discovery--that
girl ..."

I broke off, and clutching the table with both hands, sat listening
intently. From the room behind me, the opium-room, whose entrance was
less than two paces from where we sat, came a sound of dragging and
tapping! Slowly, cautiously, I began to turn my head; when a sudden
outburst of simian chattering from the _fan-tan_ players drowned that
other sinister sound.

"You heard it, Doctor!" hissed Fletcher.

"The man with the limp!" I said hoarsely; "he is in there! Fletcher!
I am utterly confused. I believe this place to hold the key to the
whole mystery, I believe ..."

Fletcher gave me a warning glance--and, turning anew, I saw Zarmi
approaching with her sinuous gait, carrying two glasses and jug upon
the ornate tray. These she set down upon the table; then stood
spinning the salver cleverly upon the point of her index finger and
watching us through half-closed eyes.

My companion took out some loose coins, but the girl thrust the
proffered payment aside with her disengaged hand, the salver still
whirling upon the upraised finger of the other.

"Presently you pay for drink," she said. "You do something for me--eh?"

"Yep," replied Fletcher nonchalantly, watering the rum in the
tumblers. "What time?"

"Presently I tell you. You stay here. This one a strong feller?"--
indicating myself.

"Sure," drawled Fletcher; "strong as a mule he is."

"All right. I give him one little kiss if he good boy!"

Tossing the tray in the air she caught it, rested its edge upon her
hip, turned, and walked away down the room, puffing her cigarette.

"Listen," I said, bending across the table, "it was Zarmi who drove
the cab that came for Nayland Smith to-day!"

"My God!" whispered Fletcher, "then it was nothing less than the hand
of Providence that brought us here to-night. Yes! I know how you feel,
Doctor!--but we must play our cards as they're dealt to us. We must
wait--wait."

Out from the den of the opium-smokers came Zarmi, one hand resting
upon her hip and the other uplifted, a smoldering yellow cigarette
held between the first and second fingers. With a movement of her
eyes she summoned us to join her, then turned and disappeared again
through the low doorway.

The time for action was arrived--we were to see behind the scenes of