umstances, and that
the man who had owned it--the name was different--had disappeared with
his wife. The descriptions agreed. When I learned that the missing man
was devoted to entomology the identification was complete."

The darkness was rising, but much was still hidden by the shadows.

"If this woman is in truth his wife, where does Mrs. Laura Lyons come
in?" I asked.

"That is one of the points upon which your own researches have shed a
light. Your interview with the lady has cleared the situation very
much. I did not know about a projected divorce between herself and her
husband. In that case, regarding Stapleton as an unmarried man, she
counted no doubt upon becoming his wife."

"And when she is undeceived?"

"Why, then we may find the lady of service. It must be our first duty
to see her--both of us--tomorrow. Don't you think, Watson, that you are
away from your charge rather long? Your place should be at Baskerville
Hall."

The last red streaks had faded away in the west and night had settled
upon the moor. A few faint stars were gleaming in a violet sky.

"One last question, Holmes," I said as I rose. "Surely there is no need
of secrecy between you and me. What is the meaning of it all? What is he
after?"

Holmes's voice sank as he answered:

"It is murder, Watson--refined, cold-blooded, deliberate murder. Do not
ask me for particulars. My nets are closing upon him, even as his are
upon Sir Henry, and with your help he is already almost at my mercy.
There is but one danger which can threaten us. It is that he should
strike before we are ready to do so. Another day--two at the most--and
I have my case complete, but until then guard your charge as closely
as ever a fond mother watched her ailing child. Your mission today has
justified itself, and yet I could almost wish that you had not left his
side. Hark!"

A terrible scream--a prolonged yell of horror and anguish--burst out of
the silence of the moor. That frightful cry turned the blood to ice in
my veins.

"Oh, my God!" I gasped. "What is it? What does it mean?"

Holmes had sprung to his feet, and I saw his dark, athletic outline at
the door of the hut, his shoulders stooping, his head thrust forward,
his face peering into the darkness.

"Hush!" he whispered. "Hush!"

The cry had been loud on account of its vehemence, but it had pealed out
from somewhere far off on the shadowy plain. Now it burst upon our ears,
nearer, louder, more urgent