What with the excitement of the discovery, the walk home under the stars in wet shoes and draggled skirts, and getting up-stairs and undressed without rousing Liddy, I was completely used up. What to do with my boots was the greatest puzzle of all, there being no place in the house safe from Liddy, until I decided to slip upstairs the next morning and drop them into the hole the "ghost" had made in the trunk-room wall.

I went asleep as soon as I reached this decision, and in my dreams I lived over again the events of the night. Again I saw the group around the silent figure on the grass, and again, as had happened at the grave, I heard Alex's voice, tense and triumphant:

"Then we've got them," he said. Only, in my dreams, he said it over and over until he seemed to shriek it in my ears.

I wakened early, in spite of my fatigue, and lay there thinking. Who was Alex? I no longer believed that he was a gardener. Who was the man whose body we had resurrected? And where was Paul Armstrong? Probably living safely in some extraditionless country on the fortune he had stolen. Did Louise and her mother know of the shameful and wicked deception? What had Thomas known, and Mrs. Watson? Who was Nina Carrington?

This last question, it seemed to me, was answered. In some way the woman had learned of the substitution, and had tried to use her knowledge for blackmail. Nina Carrington's own story died with her, but, however it happened, it was clear that she had carried her knowledge to Halsey the afternoon Gertrude and I were looking for clues to the man I had shot on the east veranda. Halsey had been half crazed by what he heard; it was evident that Louise was marrying Doctor Walker to keep the shameful secret, for her mother's sake. Halsey, always reckless, had gone at once to Doctor Walker and denounced him. There had been a scene, and he left on his way to the station to meet and notify Mr. Jamieson of what he had learned. The doctor was active mentally and physically. Accompanied perhaps by Riggs, who had shown himself not overscrupulous until he quarreled with his employer, he had gone across to the railroad embankment, and, by jumping in front of the car, had caused Halsey to swerve. The rest of the story we knew.

That was my reconstructed theory of that afternoon and evening: it was almost correct--not quite.

There was a telegram that morning from Gertrude.

"Halsey conscious and improving. Probably home in day or so. GERTRUDE."

With Halsey found and improving in health, and with at last something to work on, I began that day, Thursday, with fresh courage. As Mr. Jamieson had said, the lines were closing up. That I was to be caught and almost finished in the closing was happily unknown to us all.

It was late when I got up. I lay in my bed, looking around the four walls of the room, and trying to imagine behind what one of them a secret chamber might lie. Certainly, in daylight, Sunnyside deserved its name: never was a house more cheery and open, less sinister in general appearance. There was not a corner apparently that was not open and above-board, and yet, somewhere behind its handsomely papered walls I believed firmly that there lay a hidden room, with all the possibilities it would involve.

I made a mental note to have the house measured during the day, to discover any discrepancy between the outer and inner walls, and I tried to recall again the exact wording of the paper Jamieson had found.

The slip had said "chimney." It was the only clue, and a house as large as Sunnyside was full of them. There was an open fireplace in my dressing-room, but none in the bedroom, and as I lay there, looking around, I thought of something that made me sit up suddenly. The trunk-room, just over my head, had an open fireplace and a brick chimney, and yet, there was nothing of the kind in my room. I got out of bed and examined the opposite wall closely. There was apparently no flue, and I knew there was none in the hall just beneath. The house was heated by steam, as I have said before. In the living-room was a huge open fireplace, but it was on the other side.

Why did the trunk-room have both a radiator and an open fireplace? Architects were not usually erratic! It was not fifteen minutes before I was up-stairs, armed with a tape-measure in lieu of a foot-rule, eager to justify Mr. Jamieson's opinion of my intelligence, and firmly resolved not to tell him of my suspicion until I had more than theory to go on. The hole in the trunk-room wall still yawned there, between the chimney and the outer wall. I examined it again, with no new result. The space between the brick wall and the plaster and lath one, however, had a new significance. The hole showed only one side of the chimney, and I determined to investigate what lay in the space on the other side of the mantel.

I worked feverishly. Liddy had gone to the village to market, it being her firm belief that the store people sent short measure unless she watched the scales, and that, since the failure of the Traders' Bank, we must watch the corners; and I knew that what I wanted to do must be done before she came back. I had no tools, but after rummaging around I found a pair of garden scissors and a hatchet, and thus armed, I set to work. The plaster came out easily: the lathing was more obstinate. It gave under the blows, only to spring back into place again, and the necessity for caution made it doubly hard.

I had a blister on my palm when at last the hatchet went through and fell with what sounded like the report of a gun to my overstrained nerves. I sat on a trunk, waiting to hear Liddy fly up the stairs, with the household behind her, like the tail of a comet. But nothing happened, and with a growing feeling of uncanniness I set to work enlarging the opening.

The result was absolutely nil. When I could hold a lighted candle in the opening, I saw precisely what I had seen on the other side of the chimney--a space between the true wall and the false one, possibly seven feet long and about three feet wide. It was in no sense of the word a secret chamber, and it was evident it had not been disturbed since the house was built. It was a supreme disappointment.

It had been Mr. Jamieson's idea that the hidden room, if there was one, would be found somewhere near the circular staircase. In fact, I knew that he had once investigated the entire length of the clothes chute, hanging to a rope, with this in view. I was reluctantly about to concede that he had been right, when my eyes fell on the mantel and fireplace. The latter had evidently never been used: it was closed with a metal fire front, and only when the front refused to move, and investigation showed that it was not intended to be moved, did my spirits revive.

I hurried into the next room. Yes, sure enough, there was a similar mantel and fireplace there, similarly closed. In both rooms the chimney flue extended well out from the wall. I measured with the tape-line, my hands trembling so that I could scarcely hold it. They extended two feet and a half into each room, which, with the three feet of space between the two partitions, made eight feet to be accounted for. Eight feet in one direction and almost seven in the other--what a chimney it was!

But I had only located the hidden room. I was not in it, and no amount of pressing on the carving of the wooden mantels, no search of the floors for loose boards, none of the customary methods availed at all. That there was a means of entrance, and probably a simple one, I could be certain. But what? What would I find if I did get in? Was the detective right, and were the bonds and money from the Traders' Bank there? Or was our whole theory wrong? Would not Paul Armstrong have taken his booty with him? If he had not, and if Doctor Walker was in the secret, he would have known how to enter the chimney room. Then--who had dug the other hole in the false partition?