I stood looking at the empty bed. The coverings had been thrown back, and Louise's pink silk dressing-gown was gone from the foot, where it had lain. The night lamp burned dimly, revealing the emptiness of the place. I picked it up, but my hand shook so that I put it down again, and got somehow to the door.

There were voices in the hall and Gertrude came running toward me.

"What is it?" she cried. "What was that sound? Where is Louise?"

"She is not in her room," I said stupidly. "I think--it was she--who screamed."

Liddy had joined us now, carrying a light. We stood huddled together at the head of the circular staircase, looking down into its shadows. There was nothing to be seen, and it was absolutely quiet down there. Then we heard Halsey running up the main staircase. He came quickly down the hall to where we were standing.

"There's no one trying to get in. I thought I heard some one shriek. Who was it?"

Our stricken faces told him the truth.

"Some one screamed down there," I said. "And--and Louise is not in her room."

With a jerk Halsey took the light from Liddy and ran down the circular staircase. I followed him, more slowly. My nerves seemed to be in a state of paralysis: I could scarcely step. At the foot of the stairs Halsey gave an exclamation and put down the light.

"Aunt Ray," he called sharply.

At the foot of the staircase, huddled in a heap, her head on the lower stair, was Louise Armstrong. She lay limp and white, her dressing-gown dragging loose from one sleeve of her night-dress, and the heavy braid of her dark hair stretching its length a couple of steps above her head, as if she had slipped down.

She was not dead: Halsey put her down on the floor, and began to rub her cold hands, while Gertrude and Liddy ran for stimulants. As for me, I sat there at the foot of that ghostly staircase-- sat, because my knees wouldn't hold me--and wondered where it would all end. Louise was still unconscious, but she was breathing better, and I suggested that we get her back to bed before she came to. There was something grisly and horrible to me, seeing her there in almost the same attitude and in the same place where we had found her brother's body. And to add to the similarity, just then the hall clock, far off, struck faintly three o'clock.

It was four before Louise was able to talk, and the first rays of dawn were coming through her windows, which faced the east, before she could tell us coherently what had occurred. I give it as she told it. She lay propped in bed, and Halsey sat beside her, unrebuffed, and held her hand while she talked.

"I was not sleeping well," she began, "partly, I think, because I had slept during the afternoon. Liddy brought me some hot milk at ten o'clock and I slept until twelve. Then I wakened and--I got to thinking about things, and worrying, so I could not go to sleep.

"I was wondering why I had not heard from Arnold since the--since I saw him that night at the lodge. I was afraid he was ill, because--he was to have done something for me, and he had not come back. It must have been three when I heard some one rapping. I sat up and listened, to be quite sure, and the rapping kept up. It was cautious, and I was about to call Liddy.

Then suddenly I thought I knew what it was. The east entrance and the circular staircase were always used by Arnold when he was out late, and sometimes, when he forgot his key, he would rap and I would go down and let him in. I thought he had come back to see me--I didn't think about the time, for his hours were always erratic. But I was afraid I was too weak to get down the stairs.

The knocking kept up, and just as I was about to call Liddy, she ran through the room and out into the hall. I got up then, feeling weak and dizzy, and put on my dressing-gown. If it was Arnold, I knew I must see him.

"It was very dark everywhere, but, of course, I knew my way. I felt along for the stair-rail, and went down as quickly as I could. The knocking had stopped, and I was afraid I was too late. I got to the foot of the staircase and over to the door on to the east veranda. I had never thought of anything but that it was Arnold, until I reached the door. It was unlocked and opened about an inch. Everything was black: it was perfectly dark outside. I felt very queer and shaky. Then I thought perhaps Arnold had used his key; he did--strange things sometimes, and I turned around. Just as I reached the foot of the staircase I thought I heard some one coming. My nerves were going anyhow, there in the dark, and I could scarcely stand. I got up as far as the third or fourth step; then I felt that some one was coming toward me on the staircase. The next instant a hand met mine on the stair-rail. Some one brushed past me, and I screamed. Then I must have fainted."

That was Louise's story. There could be no doubt of its truth, and the thing that made it inexpressibly awful to me was that the poor girl had crept down to answer the summons of a brother who would never need her kindly offices again. Twice now, without apparent cause, some one had entered the house by means of the east entrance: had apparently gone his way unhindered through the house, and gone out again as he had entered. Had this unknown visitor been there a third time, the night Arnold Armstrong was murdered? Or a fourth, the time Mr. Jamieson had locked some one in the clothes chute?

Sleep was impossible, I think, for any of us. We dispersed finally to bathe and dress, leaving Louise little the worse for her experience. But I determined that before the day was over she must know the true state of affairs. Another decision I made, and I put it into execution immediately after breakfast. I had one of the unused bedrooms in the east wing, back along the small corridor, prepared for occupancy, and from that time on, Alex, the gardener, slept there. One man in that barn of a house was an absurdity, with things happening all the time, and I must say that Alex was as unobjectionable as any one could possibly have been.

The next morning, also, Halsey and I made an exhaustive examination of the circular staircase, the small entry at its foot, and the card-room opening from it. There was no evidence of anything unusual the night before, and had we not ourselves heard the rapping noises, I should have felt that Louise's imagination had run away with her. The outer door was closed and locked, and the staircase curved above us, for all the world like any other staircase.

Halsey, who had never taken seriously my account of the night Liddy and I were there alone, was grave enough now. He examined the paneling of the wainscoting above and below the stairs, evidently looking for a secret door, and suddenly there flashed into my mind the recollection of a scrap of paper that Mr. Jamieson had found among Arnold Armstrong's effects. As nearly as possible I repeated its contents to him, while Halsey took them down in a note-book.

"I wish you had told me that before," he said, as he put the memorandum carefully away. We found nothing at all in the house, and I expected little from any examination of the porch and grounds. But as we opened the outer door something fell into the entry with a clatter. It was a cue from the billiard-room.

Halsey picked it up with an exclamation.

"That's careless enough," he said. "Some of the servants have been amusing themselves."

I was far from convinced. Not one of the servants would go into that wing at night unless driven by dire necessity. And a billiard cue! As a weapon of either offense or defense it was an absurdity, unless one accepted Liddy's hypothesis of a ghost, and even then, as Halsey pointed out, a billiard-playing ghost would be a very modern evolution of an ancient institution.

That afternoon we, Gertrude, Halsey and I, attended the coroner's inquest in town. Doctor Stewart had been summoned also, it transpiring that in that early Sunday morning, when Gertrude and I had gone to our rooms, he had been called to view the body. We went, the four of us, in the machine, preferring the execrable roads to the matinee train, with half of Casanova staring at us. And on the way we decided to say nothing of Louise and her interview with her stepbrother the night he died. The girl was in trouble enough as it was.