AT THE house, no one was visible with the exception of Billy Walker, who, on the porch, reclined in a large rocking-chair, displaying his customary masterly inactivity, the while he contemplated the tip of a particularly black cigar, which he had not troubled to light for the sufficient reason that there were no matches nearer than the hall. The information concerning the recess within the walls was duly imparted to him, and he followed his two friends and the boatman to the closet in the hallway upstairs. The others were inclined to jeer at Billy Walker for this surprising show of activity on his part. But it was a jibe from Roy that put the lethargic one on his mettle. It came after Jake had cut through the paper in a panel from floor to ceiling, by which was revealed a black opening into the space beyond.

“And, above all,” Roy said, entreatingly, “don’t, I beg of you, Billy, let your rash impetuosity lead you to squeezing in here. Remember your paunch, and be warned in time.”

It is certain that, until this moment, Billy had had no slightest thought of thus venturing into the opening. But human nature is often contrary, and, though ordinarily Billy vastly preferred taunts to physical exertion, in this instance it so chanced that his friend’s remark touched him in a sensitive spot. He said nothing at the time, however, contenting himself with a sudden, valiant resolve. So, after candles had been brought, and his two friends had squeezed themselves, one after the other into the opening, Billy Walker, in his turn, essayed an entrance—to the considerable astonishment of Jake, who remained in the hall.

“Better take a candle, sir,” he suggested; and he offered one already lighted.

It was accepted, and, holding it high before him, Billy surveyed the region into which he meant to venture thus intrepidly. By the flickering light, he beheld a very narrow passage, in which, toward the farther end, he could distinguish the deeper shadow that he knew to be Roy, who had been the second to enter. There could be no doubt as to the person’s identity, since there was no room in which one person could pass another unless by climbing.

At sight of the limited space, Billy was assailed with pangs of regret that he had so vaingloriously undertaken the adventure. Nevertheless, he felt that it was now too late to retreat, and, with a sigh of disgust, he thrust himself forward. He had observed in his brief examination that there was no flooring, but merely the naked joists, over which he must make his way very cautiously, stepping accurately from one to another. Warily, then, he went forward, using every caution. It was by no means pleasant going, because of the precarious footing, and, too, because of the fact that his broad shoulders were unduly constricted by the walls on either side. Disaster came when a nail caught in the sleeve of his coat, just as he gave a lunge forward. The unexpected restraint threw him out of balance; in recovering himself, he dropped the candle. On the instant, his imagination was filled with glaring visions of the house in flames. Alarmed he stooped his heavy body swiftly—too swiftly, alas—for his feet slipped from the narrow supports. He fell heavily. His hands and arms shot through the plastering that ceiled the room beneath. The violence of the impact was such that a large square of the plastering broke away, and went clattering to the floor of the room below. But, before the noise of its falling sounded, Billy Walker had heard another sound, a sharp cry of surprise, or fear. Through the rain of plaster, his eyes caught one glimpse of a darting figure; his ears distinguished from out the other din a scurry of steps over the polished floor. Even in the turmoil of the moment, Billy automatically noted these things. But, at the time, he gave no heed whatever to them, his one desire just then was to escape from this horrible predicament without the loss of an instant. To that end, he immediately began to back out, with never another thought to the candle, which, however, had been extinguished by the fall.

Slowly and wrathfully, Billy Walker made his laborious retreat on hands and knees backward from the scene of his exploits. His friends, startled by the noise behind them, had managed to face about, and to hurry toward him, and now they stood, one behind the other, peering at the prostrate one; at first in amazement over his presence there at all; then, in alarm over his condition; finally, reassured, in hilarious enjoyment of the catastrophe that had befallen him. Their presence and comments did not tend to soothe the outraged feelings of the victim as he wearily crept, retrograde, into the closet, and at last scrambled to his feet in the hallway. Jake was so discreet as to say nothing at all, which reticence gave him a place for all time in the unhappy man’s esteem, despite the fact that the disaster had come from accepting the proffered candle. The others, unfortunately, were not so restrained, and their remarks came near to offending Billy Walker; certainly, they increased his exasperation against the event that had made him ridiculous. But, after a little, he contrived a diversion:

“I hope that plastering didn’t hurt anybody when it fell,” he exclaimed, of a sudden.

Jake shook his head.

“Nope!” he declared. “Thar wa’n’t nobody downstairs, I guess, Marthy’s out at the back, lookin’ arter her flower garden, and thar wa’n’t nobody else round when we come up.”

“But there was someone in the room downstairs,” Billy persisted. “I heard a cry, just as my fists went through the plastering, and then, along with the other noise, I heard the steps of someone running out.”

“Was it a man or a woman?” Roy asked.

Billy shook his head.

“Really, I haven’t the least idea,” he answered, “You see, I was pretty well occupied at the moment with my own affairs, and I didn’t pay a particle of attention to anything else.”

“Anyhow, I don’t see that it matters much,” Saxe declared. “It’s plain that you didn’t hurt anyone seriously, or we’d have heard of it before this; it didn’t wound Mrs. Dustin, or Chris, for here they both come now.” He waved his hand toward the stairs, and the others turned to see the two hurrying up.

Mrs. Dustin was voluble, and mightily relieved to learn that her precious Jake had suffered no harm. The mild, black eyes of Mrs. West’s servant twinkled with amused excitement, when he was informed as to the nature of the happening. They, too, were puzzled on hearing that someone had been in the music-room at the time of the accident.

The three friends went down to the porch, which was still deserted. Billy, who had cast a disgusted glance on the litter in the drawing-room in passing, sighed lugubriously, as he sank back into the rocking-chair.

“No more thrilling adventures by field and flood for me,” he boomed. “I have had my bellyful, all at once. Let the cobbler stick to his last, and let me stick to my chair. I got too confoundedly energetic, and I’m old enough to know better. I’ve messed up the place shockingly, which means so much extra work for the industrious Mrs. Dustin, whose amiable, but foolish husband got me into this idiotic scrape. You would have found that there was no gold in the place without my assistance; and, unfortunately, I’ve incurred a financial penalty for my misplaced intrusiveness—into the plastering—and when the repairs of Miss West’s ceiling shall have been accomplished, it will be my melancholy duty to foot the bill. Oh, misery!”

The others laughed with the unfortunate, who was now again restored to his usual good humor. But, presently, Saxe spoke in a puzzled voice:

“You really must have been mistaken, Billy, about having heard someone down below you, in the music-room.”

Billy Walker snorted indignantly.

“I may possibly be a trifle languorous physically in some ways on occasion,” he retorted, “but I assure you that my ears are quick enough. I was not mistaken. I heard just what I told you I heard, and I saw, too.”

The others were unaware that Billy did not exaggerate the excellent quality of his hearing, and, in consequence, they found themselves at a loss. It was Roy, the suspicious, who finally voiced the idea that was bound to find lodgment in their minds. When he spoke, it was in a tone of conviction:

“The ubiquitous Masters, of course!”

Saxe nodded assent.

“Spying again,” he agreed. “We know that he’s capable of it.” He turned to Billy Walker, inquiringly.

“The fellow is undoubtedly open to suspicion, after what you caught him at the other day.” Billy admitted. “Equally of course, we haven’t a shred of evidence against him.”

“That doesn’t matter a bit, as long as we have the moral certainty,” Saxe argued. “But the real gist of the problem is: What on earth is the fellow up to, anyhow?”

“It’s just pure cussedness,” Roy asserted, his face hardening. “One look at him is enough to warn anyone that he’s spoiling for mischief. He’s a rotter, that’s all.”

Billy Walker shook his head, authoritatively.

“You’re wrong, as usual,” he announced, with unpleasant frankness. “As a matter of fact, our friend, the enemy, has a motive other than sheer deviltry.”

The others regarded the speaker in surprise, whereat Billy Walker nodded his head vigorously a number of times, and looked very wise indeed.

“Yes,” he continued, with much complacency. “After you had told me the incident of his listening to your talk together, I grappled with the problem of the engineer’s not minding his own business, and I presently came on the obvious solution of the puzzle.” He paused, expectantly.

“Well, what was it?” Roy demanded, impatiently. He was still smarting a little from Billy’s sweeping statement as to his own habit of inaccuracy. Saxe, too, showed a keen curiosity in his face.

“The simple truth of the matter is this,” the oracle resumed, when he felt that he had sufficiently whetted their interest by delay. “This man, Masters, has a mind to lay hold on Abernethey’s treasure himself.” He stared triumphantly at first one and then the other of his hearers.

The effect on them was enough to satisfy the purveyor of information. Roy fairly gaped in amazement, while Saxe manifested first astonishment, then incredulity, which he voiced baldly:

“Absurd!” he cried.

But Billy Walker was prepared to maintain his contention with arguments, and forthwith he did so. And, at the last, Billy made a shrewd suggestion, which, by a totally different method, arrived at the conclusion already reached by Roy through his vaunted sixth sense.

“You may have wondered a little,” the oracle said, “that I should have made no particular remonstrance when you incontinently gave up the search commanded by immutable logic. Well, as a matter of fact, I myself would have suggested the uselessness of further effort along those lines. You see, the affair lies thus.” He paused for a moment, and pursed his lips, as one preparing for didactic discourse. “This chap, Masters, is on terms of considerable intimacy, I judge, with the girl who was the secretary of the late Mr. Abernethey. Moreover, he was here, on the spot. There can be no question that, sooner or later, he learned the facts from her concerning the last will and testament of the eccentric miser. Thereupon, he determined to go treasure-hunting on his own account. He was on the job instanter, so to speak. In fact, I’m quite willing to eat my hat, which is an especially indigestible variety of Stetson, if the cottage has not already been searched with great thoroughness by our industrious antagonist.” Billy stared at his two friends contentedly out of his small, dull eyes, and his heavy face wrinkled into a smile.

The result of his words was all that he could have desired.

“The infernal sneak!” Roy exclaimed, violently. His eyes grew hard, his mouth set, with the slight forward push of the jaw. In Saxe’s face, too, anger was plain. “To think of a nice girl being fooled like that!” Roy continued furiously, after an interval of silence. “But we’ll land the robber somehow. If we don’t, I’ll find some excuse for beating him up.”

“Never mind the pummeling,” Billy counseled. “Just you keep your eyes open that he doesn’t beat you—to the money. For the present, that’s more important than jealous rows.” At this remark, which showed that the scholar was more observant than might have been supposed in a field so foreign to his usual investigations, Roy blushed for the first time in many years, and Saxe was so rude as to titter aloud.

It was at this moment that David appeared from around the north end of the cottage. Forthwith, he was made familiar with all that had happened during the period of his absence, together with the lively suspicions entertained against the engineer. When the tale had been told, David took a few minutes for reflection before he spoke.“I’m willing to believe anything against that ornery critter,” he remarked at last, with his big eyes twinkling; “but I am, before all else, a just man. You’ve got to leave Masters out on this last deal. As a matter of fact, he has a perfectly good alibi; I wanted a line on the rapscallion, and so I fairly forced myself on him this morning—to his disgust. But he didn’t think it quite prudent, I guess, to be out-and-out rude to me. For the last two hours Masters and I have been together, strolling chummily over the hills and far away.”