ngle in the blackness as before.
A few feet away in the hall was the spot where the body of Arnold
Armstrong had been found. I was a bit nervous, and I put my hand on
Halsey's sleeve. Suddenly, from the top of the staircase above us came
the sound of a cautious footstep. At first I was not sure, but
Halsey's attitude told me he had heard and was listening. The step,
slow, measured, infinitely cautious, was nearer now. Halsey tried to
loosen my fingers, but I was in a paralysis of fright.

The swish of a body against the curving rail, as if for guidance, was
plain enough, and now whoever it was had reached the foot of the
staircase and had caught a glimpse of our rigid silhouettes against the
billiard-room doorway. Halsey threw me off then and strode forward.

"Who is it?" he called imperiously, and took a half dozen rapid strides
toward the foot of the staircase. Then I heard him mutter something;
there was the crash of a falling body, the slam of the outer door, and,
for an instant, quiet. I screamed, I think. Then I remember turning
on the lights and finding Halsey, white with fury, trying to untangle
himself from something warm and fleecy. He had cut his forehead a
little on the lowest step of the stairs, and he was rather a ghastly
sight.

He flung the white object at me, and, jerking open the outer door,
raced into the darkness.

Gertrude had come on hearing the noise, and now we stood, staring at
each other over--of all things on earth--a white silk and wool blanket,
exquisitely fine! It was the most unghostly thing in the world, with
its lavender border and its faint scent. Gertrude was the first to
speak.

"Somebody--had it?" she asked.

"Yes. Halsey tried to stop whoever it was and fell. Gertrude, that
blanket is not mine. I have never seen before."

She held it up and looked at it: then she went to the door on to the
veranda and threw it open. Perhaps a hundred feet from the house were
two figures, that moved slowly toward us as we looked.

When they came within range of the light, I recognized Halsey, and with
him Mrs. Watson, the housekeeper.

CHAPTER XII

ONE MYSTERY FOR ANOTHER

The most commonplace incident takes on a new appearance if the
attendant circumstances are unusual. There was no reason on earth why
Mrs. Watson should not have carried a blanket down the east wing
staircase, if she so desired. But to take a blanket down at eleven
o'clock at night, with every pre