Bromley had been a week in hospital at the great house in the upper valley, and was recovering as rapidly as a clean-living, well-ancestored man should, when Ballard was surprised one morning by a descent of the entire Castle 'Cadia garrison, lacking only the colonel and Miss Cauffrey, upon the scene of activities at the dam.

The chief of construction had to flog himself sharply into the hospitable line before he could make the invaders welcome. He had a workingman's shrewd impatience of interruptions; and since the accident which had deprived him of his assistant, he had been doing double duty. On this particular morning he was about to leave for a flying round of the camps on the railroad extension; but he reluctantly countermanded the order for the locomotive when he saw Elsa picking the way for her guests among the obstructions in the stone yard.

"Please—oh, please don't look so inhospitable!" she begged, in well-simulated dismay, when the irruption of sight-seers had fairly surrounded him. "We have driven and fished and climbed mountains and played children's games at home until there was positively nothing else to do. Pacify him, Cousin Janet—he's going to warn us off!"

Ballard laughingly disclaimed any such ungracious intention, and proceeded to prove his words by deeds. Young Blacklock and Bigelow were easily interested in the building details; the women were given an opportunity to see the inside workings of the men's housekeeping in the shacks, the mess-tent and the camp kitchen; the major was permitted and encouraged to be loftily critical of everything; and Wingfield—but Ballard kept the playwright carefully tethered in a sort of moral hitching-rope, holding the end of the rope in his own hands.

Once openly committed as entertainer, the young Kentuckian did all that could be expected of him—and more. When the visitors had surfeited themselves on concrete-mixing and stone-laying and camp housekeeping, the chief engineer had plank seats placed on a flat car, and the invaders were whisked away on an impromptu and personally conducted railway excursion to some of the nearer ditch camps.

Before leaving the headquarters, Ballard gave Fitzpatrick an Irish hint; and when the excursionists returned from the railway jaunt, there was a miraculous luncheon served in the big mess-tent. Garou, the French-Canadian camp cook, had a soul above the bare necessities when the occasion demanded; and he had Ballard's private commissary to draw upon.

After the luncheon Ballard let his guests scatter as they pleased, charging himself, as before, particularly with the oversight and wardenship of Mr. Lester Wingfield. There was only one chance in a hundred that the playwright, left to his own devices, might stumble upon the skeleton in the camp closet. But the Kentuckian was determined to make that one chance ineffective.

Several things came of the hour spent as Wingfield's keeper while the others were visiting the wing dam and the quarry, the spillway, and the cut-off tunnel, under Fitzpatrick as megaphonist. One of them was a juster appreciation of the playwright as a man and a brother. Ballard smiled mentally when he realised that his point of view had been that of the elemental lover, jealous of a possible rival. Wingfield was not half a bad sort, he admitted; a little inclined to pose, since it was his art to epitomise a world of poseurs; an enthusiast in his calling; but at bottom a workable companion and the shrewdest of observers.

In deference to the changed point of view, the Kentuckian did penance for the preconceived prejudice and tried to make the playwright's insulation painless. The sun shone hot on the stone yard, and there was a jar of passable tobacco in the office adobe: would Wingfield care to go indoors and lounge until the others came to a proper sense of the desirability of shade and quietude on a hot afternoon?

Wingfield would, gladly. He confessed shamelessly to a habit of smoking his after-luncheon pipe on his back. There was a home-made divan in the office quarters, with cushions and blanket coverings, and Ballard found the tobacco-jar and a clean pipe; a long-stemmed "churchwarden," dear to the heart of a lazy man.

"Now this is what I call solid comfort," said the playwright, stretching his long legs luxuriously on the divan. "A man's den that is a den, and not a bric-a-brac shop masquerading under the name, a good pipe, good tobacco, and good company. You fellows have us world-people faded to a shadow when it comes to the real thing. I've felt it in my bones all along that I was missing the best part of this trip by not getting in with you down here. But every time I've tried to break away, something else has turned up."

Ballard was ready with his bucket of cold water.

"You haven't missed anything. There isn't much in a construction camp to invite the literary mind, I should say." And he tried to make the saying sound not too inhospitable.

"Oh, you're off wrong, there," argued the playwright, with cheerful arrogance. "You probably haven't a sense of the literary values; a good many people haven't—born blind on that side, you know. Now, Miss Van Bryck has the seeing eye, to an educated finish. She tells me you have a dramatic situation down here every little so-while. She told me that story of yours about the stone smashing into your office in the middle of the night. That's simply ripping good stuff—worlds of possibilities in a thing like that, don't you know? By the way, this is the room, isn't it? Does that patch in the ceiling cover the hole?"

Ballard admitted the fact, and strove manfully to throw the switch ahead of the querist to the end that the talk might be shunted to some less dangerous topic.

"Hang the tobacco!" snapped the guest irritably, retorting upon Ballard's remark about the quality of his pet smoking mixture. "You and Miss Craigmiles seem to be bitten with the same exasperating mania for subject-changing. I'd like to hear that rock-throwing story at first hands, if you don't mind."

Having no good reason for refusing point-blank, Ballard told the story, carefully divesting it of all the little mystery thrills which he had included for Miss Dosia's benefit.

"Um!" commented Wingfield, at the close of the bald narration. "It would seem to have lost a good bit in the way of human interest since Miss Van Bryck repeated it to me. Did you embroider it for her? or did she put in the little hemstitchings for me?"

Ballard laughed.

"I am sorry if I have spoiled it for you. But you couldn't make a dramatic situation out of a careless quarryman's overloading of a shot-hole."

"Oh, no," said the playwright, apparently giving it up. And he smoked his pipe out in silence.

Ballard thought the incident was comfortably dead and buried, but he did not know his man. Long after Wingfield might be supposed to have forgotten all about the stone catapulting, he sat up suddenly and broke out again.

"Say! you explained to Miss Dosia that the stone couldn't possibly have come from the quarry without knocking the science of artillery into a cocked hat. She made a point of that."

"Oh, hold on!" protested the Kentuckian. "You mustn't hold me responsible for a bit of dinner-table talk with a very charming young woman. Perhaps Miss Dosia wished to be mystified. I put it to you as man to man; would you have disappointed her?"

The playwright's laugh showed his fine teeth.

"They tell me you are at the top of the heap in your profession, Mr. Ballard, and I can easily believe it. But I have a specialty, too, and I'm no slouch in it. My little stunt is prying into the inner consciousness of things. Obviously, there is a mystery—a real mystery—about this stone-throwing episode, and for some reason you are trying to keep me from dipping into it. Conversely, I'd like to get to the bottom of it. Tell me frankly, is there any good reason why I shouldn't?"

Ballard's salvation for this time personified itself in the figure of Contractor Fitzpatrick darkening the door of the office to ask a "question of information," as he phrased it. Hence there was an excuse for a break and a return to the sun-kissed stone yard.

The engineer purposefully prolonged the talk with Fitzpatrick until the scattered sight-seers had gathered for a descent, under Jerry Blacklock's lead, to the great ravine below the dam where the river thundered out of the cut-off tunnel. But when he saw that Miss Craigmiles had elected to stay behind, and that Wingfield had attached himself to the younger Miss Cantrell, he gave the contractor his information boiled down into a curt sentence or two, and hastened to join the stay-behind.

"You'll melt, out here in the sun," he said, overtaking her as she stood looking down into the whirling vortex made by the torrent's plunge into the entrance of the cut-off tunnel.

She ignored the care-taking phrase as if she had not heard it.

"Mr. Wingfield?—you have kept him from getting interested in the—in the——"

Ballard nodded.

"He is interested, beyond doubt. But for the present moment I have kept him from adding anything to Miss Dosia's artless gossip. Will you permit me to suggest that it was taking rather a long chance?—your bringing him down here?"

"I know; but I couldn't help it. Dosia would have brought him on your invitation. I did everything I could think of to obstruct; and when they had beaten me, I made a party affair of it. You'll have to forgive me for spoiling an entire working day for you."

"Since it has given me a chance to be with you, I'm only too happy in losing the day," he said; and he meant it. But he let her know the worst in the other matter in an added sentence. "I'm afraid the mischief is done in Wingfield's affair, in spite of everything."

"How?" she asked, and the keen anxiety in the grey eyes cut him to the heart.

He told her briefly of the chance arousing of Wingfield's curiosity, and of the playwright's expressed determination to fathom the mystery of the table-smashing stone. Her dismay was pathetic.

"You should never have taken him into your office," she protested reproachfully. "He was sure to be reminded of Dosia's story there."

"I didn't foresee that, and he was beginning to gossip with the workmen. I knew it wouldn't be long before he would get the story of the happenings out of the men—with all the garnishings."

"You must find a way to stop him," she insisted. "If you could only know what terrible consequences are wrapped up in it!"

He waited until a stone block, dangling in the clutch of the derrick-fall above its appointed resting-place on the growing wall of masonry, had been lowered into the cement bed prepared for it before he said, soberly: "That is the trouble—I don't know. And, short of quarrelling outright with Wingfield, I don't think of any effective way of muzzling him."

"No; you mustn't do that. There is misery enough and enmity enough, without making any more. I'll try to keep him away."

"You will fail," he prophesied, with conviction. "Mr. Wingfield calls himself a builder of plots; but I can assure you from this one day's observation of him that he would much rather unravel a plot than build one."

She was silent while the workmen were swinging another great stone out over the canyon chasm. The shadow of the huge derrick-boom swept around and across them, and she shuddered as if the intangible thing had been an icy finger to touch her.

"You must help me," she pleaded. "I cannot see the way a single step ahead."

"And I am in still deeper darkness," he reminded her gently. "You forget that I do not know what threatens you, or how it threatens."

"I can't tell you; I can't tell any one," she said; and he made sure there was a sob at the catching of her breath.

As once before, he grew suddenly masterful.

"You are wronging yourself and me, Elsa, dear. You forget that your trouble is mine; that in the end we two shall be one in spite of all the obstacles that a crazy fate can invent."

She shook her head. "I told you once that you must not forget yourself again; and you are forgetting. There is one obstacle which can never be overcome this side of the grave. You must always remember that."

"I remember only that I love you," he dared; adding: "And you are afraid to tell me what this obstacle is. You know it would vanish in the telling."

She did not answer.

"You won't tell me that you are in love with Wingfield?" he persisted.

Still no reply.

"Elsa, dearest, can you look me in the eyes and tell me that you do not love me?"

She neither looked nor denied.

"Then that is all I need to know at present," he went on doggedly. "I shall absolutely and positively refuse to recognise any other obstacle."

She broke silence so swiftly that the words seemed to leap to her lips.

"There is one, dear friend," she said, with a warm upflash of strong emotion; "one that neither you nor I, nor any one can overcome!" She pointed down at the boulder-riven flood churning itself into spray in the canyon pot at their feet. "I will measure it for you—and for myself, God help us! Rather than be your wife—the mother of your children—I should gladly, joyfully, fling myself into that."

The motion he made to catch her, to draw her back from the brink of the chasm, was purely mechanical, but it served to break the strain of a situation that had become suddenly impossible.

"That was almost tragic, wasn't it?" she asked, with a swift retreat behind the barricades of mockery. "In another minute we should have tumbled headlong into melodrama, with poor Mr. Wingfield hopelessly out of reach for the note-taking process."

"Then you didn't mean what you were saying?" he demanded, trying hard to overtake the fleeing realities.

"I did, indeed; don't make me say it again. The lights are up, and the audience might be looking. See how manfully Mr. Bigelow is trying not to let Cousin Janet discover how she is crushing him!"

Out of the lower ravine the other members of the party were straggling, with Bigelow giving first aid to a breathless and panting Mrs. Van Bryck, and Wingfield and young Blacklock helping first one and then another of the four younger women. The workmen in the cutting yard were preparing to swing a third massive face-block into place on the dam; and Miss Craigmiles, quite her serene self again, was asking to be shown how the grappling hooks were made fast in the process of "toggling."

Ballard accepted his defeat with what philosophy he could muster, and explained the technical detail. Then the others came up, and the buckboards sent down from Castle 'Cadia to take the party home were seen wheeling into line at the upper end of the short foothill canyon.

"There is our recall at last, Mr. Ballard," gasped the breathless chaperon, "and I daresay you are immensely relieved. But you mustn't be too sorry for your lost day. We have had a perfectly lovely time."

"Such a delightful day!" echoed the two sharers of the common Christian name in unison; and the king's daughter added demurely: "Don't you see we are all waiting for you to ask us to come again, Mr. Ballard?"

"Oh, certainly; any time," said Ballard, coming to the surface. Notwithstanding, on the short walk up to the waiting buckboards he sank into the sea of perplexity again. Elsa's moods had always puzzled him. If they were not real, as he often suspected, they were artistically perfect imitations; and he was never quite sure that he could distinguish between the real and the simulated.

As at the present moment: the light-hearted young woman walking beside him up the steep canyon path was the very opposite of the sorely tried and anxious one who had twice let him see the effects of the anxiety, however carefully she concealed the cause.

The perplexed wonder was still making him half abstracted when he put himself in the way to help her into one of the homeward-headed vehicles. They were a little in advance of the others, and when she faced him to say good-bye, he saw her eyes. Behind the smile in them the troubled shadows were still lurking; and when the heartening word was on his lips they looked past him, dilating suddenly with a great horror.

"Look!" she cried, pointing back to the dam; and when he wheeled he saw that they were all looking; standing agape as if they had been shown the Medusa's head. The third great stone had been swung out over the dam, and, little by little, with jerkings that made the wire cables snap and sing, the grappling-hooks were losing their hold in mid-air. The yells of the workmen imperilled rose sharply above the thunder of the river, and the man at the winding-drums seemed to have lost his nerve and his head.

Young Blacklock, who was taking an engineering course in college, turned and ran back down the path, shouting like a madman. Ballard made a megaphone of his hands and bellowed an order to the unnerved hoister engineer. "Lower away! Drop it, you blockhead!" he shouted; but the command came too late. With a final jerk the slipping hooks gave way, and the three-ton cube of granite dropped like a huge projectile, striking the stonework of the dam with a crash like an explosion of dynamite.

Dosia Van Bryck's shriek was ringing in Ballard's ears, and the look of frozen horror on Elsa's face was before his eyes, when he dashed down the steep trail at Blacklock's heels. Happily, there was no one killed; no one seriously hurt. On the dam-head Fitzpatrick was climbing to a point of vantage to shout the news to the yard men clustering thickly on the edge of the cliff above, and Ballard went only far enough to make sure that there had been no loss of life. Then he turned and hastened back to the halted buckboards.

"Thank God, it's only a money loss, this time!" he announced. "The hooks held long enough to give the men time to get out of the way."

"There was no one hurt? Are you sure there was no one hurt?" panted Mrs. Van Bryck, fanning herself vigorously.

"No one at all. I'm awfully sorry we had to give you such a shock for your leave-taking, but accidents will happen, now and then. You will excuse me if I go at once? There is work to be done."

"H'm—ha! One moment, Mr. Ballard," rasped the major, swelling up like a man on the verge of apoplexy. But Mrs. Van Bryck was not to be set aside.

"Oh, certainly, we will excuse you. Please don't waste a moment on us. You shouldn't have troubled to come back. So sorry—it was very dreadful—terrible!"

While the chaperon was groping for her misplaced self-composure, Wingfield said a word or two to Dosia, who was his seat-mate, and sprang to the ground.

"Hold on a second, Ballard!" he called. "I'm going with you. What you need right now is a trained investigator, and I'm your man. Great Scott! to think that a thing like that should happen, and I should be here to see it!" And then to Miss Craigmiles, who appeared to be trying very earnestly to dissuade him: "Oh, no, Miss Elsa; I sha'n't get underfoot or be in Mr. Ballard's way; and you needn't trouble to send down for me. I can pad home on my two feet, later on."