Setting out on his aËrial trip over the Cup of Nannabijou did not prove so simple a matter as Hammond had at first conceived it would be. In the first place, he had to get permission from the department at Ottawa before the authorities at the Kam City armouries would even allow him to try out the plane. Though he despatched Inspector Little’s wire immediately after his arrival, it was Monday afternoon before a reply was forthcoming.

The next delay was in getting the machine in shape for the trip. For want of expert attention, the motors and accessories were wofully out of tune, and before he felt satisfied that they were in anything like efficient shape it was too late to make the trip Monday. On the short trial flights he made the engine still showed a disposition to sulk, but by careful handling he managed to keep it alive while in the air.

He determined to fly over the Nannabijou Limits as early as possible Monday morning. Monday night the storm came up, one of the worst experienced in Kam City in years, and the shed out on the exhibition grounds in which he had temporarily housed the machine, was unroofed by the gale and minor damages done to the wings of the plane that it took a couple of hours to repair.

The morning, however, broke crisp and clear, an ideal day for flying and making observations. From Kam City to the Nannabijou Limits was a little better than twenty miles, and Hammond figured he could make it in about twenty-five to thirty minutes at the outside.

But again he had trouble in making a start. Three times he went up and had to come down again to make fresh adjustments. It was ten o’clock before he was definitely on his way across the arm of the lake with the craterlike top of Nannabijou Mountain as his objective.

Though the wind had dropped, the lake was still creased with angry waves. He crossed Superior’s upper arm without mishap. As he neared the limits, his first unusual discovery was the immense amount of pulpwood thrown up along the North Shore and on the islands that dotted it as far as the eye could see. There was only one place all those poles could come from, the airman conjectured as his machine roared onward through the bright, sunlit upper air.

His hunch was confirmed when he came opposite the limits and secured a full view of Nannabijou Bay, empty of almost every pulp-pole.

He dropped down for a closer look. The Mounties still patrolled the waterfront, but the camp was a scene of animated chaos. Gangs of men were at work repairing the roadways riven deep by the torrents of the night before while others were engaged in removing the fallen timber that blocked every thoroughfare. He noted that the bridge over the Nannabijou River was gone and the hills were made more desolate by fresh fields of tangled windfalls.

As he swooped, Hammond glimpsed Inspector Little signalling to him to proceed direct to the Cup and return. The young airman picked out a likely looking landing place back of the limits, then shot his machine upward. He followed the course of the Nannabijou to the point where Solomon Creek made its confluence, when he swerved and followed the creek.

Below him now he could discern what had caused the flood that had swept down in the night and carried out the immense field of pulpwood boomed in the bay. The huge beaver-dam on the creek was gone, and where the lake had been, behind the dam, there remained only a slimy area of silt and mud. Thus it was brought home to him at a glance that the war between the rival lumber companies for the operating rights on the limits had been ended by the elements in favour of the North Star. . . The elements alone? He wondered. . . . Likely here was another mystery in the history of the North Star that would remain unsolved. Nobody had seemingly thought of the possibilities in case that lake of water behind the beaver-dam were set free.

Significant as all these things were, Hammond’s main interest was soon centred on the Cup of Nannabijou and its environs. As he glided over the draw in the cliffs along the creek trail to where it seemingly ended in the tunnel opening out over the rapids in the gorge he got a true perspective of the water-gate guarding the only entrance from the land side through the cliffs of the Cup. From his lofty point of observation he could note how the creek in the first place had cut a big oval-shaped “O” in the rock, leaving a high pinnacle in the centre.

But it was the man-made device for diverting the flow of water that most excited his curiosity. At the upper end, where the stream originally forked around the island of rock, was a contrivance like the walking-beam of an old-style steamship. From the ends of this beam, which sat in a steel pillar between the channels, connecting-rods reached down to sliding dams operating in slots cut in the sides of the channels. At the present moment, the dam on the western side was down, and the one on the eastern side up, thus forcing the whole volume of water from the overflow of the lake in the Cup down the latter channel, whose bed, when the dam on that side was closed forcing the water around the other way, formed a dry continuation of the creek trail to an upper tunnel leading through the cliffs and into the Cup of Nannabijou.

Chains extending from concealed mechanism below the walking-beam proved the dams to be operated by power. A tiny building, cleverly cached in a natural opening in the rocks at the west side, and from which copper wire was strung into the Cup, housed the hydro-electric plant where the current was generated. Hammond was scientific enough to conceive that the water-gate and the gong-signal near it were animated by a concealed magnet system at the simple pressing of an electric button somewhere.

As he swept into the Cup, Hammond’s discovery of the beautiful little mountain lake and the buildings above it, set off by their well-kept parklike surroundings, was even more of a revelation. From the plane it proved a wonderful picture—so wonderful that Hammond forgot he was in an area of danger until it recurred to him that here some place Josephine Stone was held captive.

But when he circled over the chateau and the wireless plant, he could discover no signs of life. He was certain if there were people about their attention would have long since been attracted by the roar of his engine. He decided to land and make an investigation in spite of the caution of Inspector Little that he should return to the camps after making observations from the air.

He slid down at a point in front of the bungalow.

The silence after quitting his machine seemed oppressive, and the place utterly deserted. He walked up on the verandah and rapped thrice on the chateau door. Receiving no answer, he tried the door. It was not locked, so he opened it and boldly entered. He was now determined to explore the building from top to bottom. The quaint, unusual appointments of the chateau at another time would have deeply interested him, but he felt he must work fast and be on the alert for surprise.

The rooms all bore the appearance of recent occupancy, but there were evidences that the house had been set in order before the departure of its people.

The sleeping chambers he examined last. All of these rooms had been swept, dusted and the beds made; but in one of them he picked up a fancy celluloid hair-comb. There was only one person on Nannabijou Limits to whom that could belong, and that was Josephine Stone.

The conviction brought home to Hammond from every quarter was that he had arrived too late. Josephine Stone’s captors must have carried her off to some other fastness. He thought of the building adjacent, but on going there he found the doors and windows securely locked. The blinds, however, were up, and he could get a clear view of all the rooms and the wireless plant inside. There was nothing else there beyond a number of empty bunks, a table and a few chairs.

It struck him that there was possibly another retreat hidden away in some other part of the Cup—perhaps up in the woods. He returned to the plane intending to make a thorough search of the area in the Cup from the air. But his engine was in a decidedly balky mood. He had a feeling it would fail him altogether, and, on an impulse of better judgment, he swung up and over the cliffs.He had barely reached the confluence of Solomon Creek with Nannabijou River when the motor went dead.

Fortunately, by skillful manipulation of the planes, he was enabled to glide safely down over the timbered sides of the mountain to the cleared area just above Nannabijou camps.

His plane was soon surrounded by wondering groups of camp workers from among whom there strode a member of the mounted force. He leaned close as Hammond was getting out of the machine.

“Inspector Little would like you to go down to his quarters at once, Mr. Hammond,” he said. “I will see that your machine is taken care of.”

III

The inspector’s genial smile and hearty handshake did much to revive Hammond’s drooping spirits over his nonsuccess in finding trace of Miss Stone. “Mighty glad to see you back safe and sound, old man,” he offered. “Find any clues up there as to the whereabouts of the young lady?”

Briefly Hammond gave a verbal report of his discoveries, adding that he was convinced Josephine was still held prisoner somewhere up in the Cup.

The inspector sat for a few moments in a brown study. “H’mph, that’s interesting at any rate,” he finally spoke up. “Your findings seem to bear out what I have already learned from other quarters.”

“I’d like to return and finish the investigation as soon as I can get the old bus in working order,” suggested Hammond.

“No, I couldn’t approve of that,” decided the inspector. “With that balky machine it would be too risky, and besides, it might give warning to the gang we’re after if they did not succeed in capturing you or doing you actual bodily harm.”

“Then what do you propose to do?”

“To go up on foot with a half dozen picked members of our force just as soon as you’ve had a bite to eat and changed your flying togs. A private detective of Gildersleeve’s—Lynch his name is—has discovered how that water-gate up there is operated, and we’re taking him along to show us how to get in.”

“Is Gildersleeve here?”

“He was, but he left for town on the early tug this morning, though I have a hunch I should have put him in custody until this whole thing is cleared up.”

“You still suspect him of underhand work?”

“Just now I hardly know what to suspect. There seems to be some unholy mystery here that’s mighty difficult to get to the bottom of. Gildersleeve may be innocent of having anything to do with the abduction of Miss Stone, but I am becoming more and more certain that there is some part he played out here he’s anxious to conceal. I expect you noticed that the beaver-dam in Solomon Creek was gone and the head of water that came down last night forced out the booms of pulpwood in the bay?”

“Yes. I imagine Gildersleeve would be wild over that.”

“Wild is no name for it. Before he left this morning he spent most of the time cursing everything and everybody. I think the man was drunk. Anyway, he insists that the North Star people blew up the dam with dynamite while the storm was on. But we can’t take any action on mere conjectures. Even if the dam were blown up the freshet left no clues behind. Our men made a thorough investigation this morning and could find no proof that the dam did not give way through natural causes. Now Gildersleeve swears he’s going after the Dominion government for damages because we did not have a patrol watching the dam. I suppose we might have taken that precaution, but no one thought of danger from that direction.”

“Without proof that the disaster occurred through preventable causes I don’t see how he can produce grounds for damages,” asserted Hammond.

“Nor I,” returned the inspector. “Furthermore, Gildersleeve has not from the first dealt on the square with us or taken us into his confidence. Off-hand, I’d say he appears to me like a man who’s been beaten to it at a game of double-cross where he was as deep-dyed as the other fellow and now he’s aching to take his spleen out on a third party.

“But come, Hammond,” urged the inspector, “you run along to the dining camp and have a snack of lunch, and as soon as you get your clothes changed we’ll make a start.”

IV

Sandy Macdougal was glad to see Hammond again, but he appeared to be particularly out of sorts and uncommunicative this morning. It was only when Hammond was leaving the dining camp that he had anything in particular to say.

“It ain’t none of my business,” he told Hammond, “but if I was asked for any advice, I’d say keep away from that Cup. There ain’t anybody white ever went up there monkeyin’ around that something didn’t happen they were sorry for.”

The little expedition which set out for the mountain was composed of Inspector Little, five of his most experienced men, Lynch the private detective and Louis Hammond. Before they struck out Inspector Little insisted there was no necessity for the civilians in the party carrying firearms and used this as an excuse for relieving Lynch of a murderous-looking revolver.

Lynch was loud in his protests that as a detective he should be allowed to carry the weapon, but it did not go with the inspector. “I am not carrying a gun myself,” he pointed out. “My men are armed and that is all that is necessary, for they are not liable to shoot unless it is a case of protecting our lives and their own.”

It was not only that he sought to guard against unnecessary bloodshed, but Inspector Little was not any too sure of his ground in entering the Cup of Nannabijou by means of force. The police held no warrant for the arrest of any one except Nathan Stubbs, the pseudo camp preacher, and the doughty inspector was far from convinced that Stubbs was up in the Cup. The only pretext on which he felt he could legally demand the privilege of entering the Cup with an armed force, in case resistance were offered, was the right to search for the missing girl, Josephine Stone.

On the other hand, his distrust of Gildersleeve was growing, along with a conviction that the mysterious happenings on Nannabijou Limits were far from being what they appeared to be on the surface. In this latter regard, he was determined not to be made the catspaw of Gildersleeve through any trickery on the part of his detective.

The journey up the mountain and along Solomon Creek trail was made in comparative silence, except for the volubility of Lynch who bored the patient inspector with wild theories as to what existed beyond the cliffs of Nannabijou.

When they reached the tunnel that opened out over the rapids of the creek, Lynch was all impatience to demonstrate his prowess in showing how the water-gate was operated. He reached up to the jutting bit of rock and fumbled for the tiny hole and inserted a match which he pressed.

There came instantly the mellow alarm of the bell above.

“Cripes, that’s sudden action for you,” he exclaimed. “I hardly pressed my finger on the match when the bell rang. It must be set on some sort of hair-trigger.”

Almost immediately the water in the channel dwindled and ceased to flow.

“That’s certainly a novel device,” declared the inspector as he stood with the others of the party staring at the stream-bed where the last trickle of water had vanished.

“Watch while I let it loose again,” cried Lynch. “Keep back, everybody, for she certainly comes down hell-bent when she’s opened.”

“Hold on! Don’t touch it!”

Inspector Little and Louis Hammond, certain they caught the sound of voices somewhere above, yelled it in unison.

But there was no stopping the irrepressible Lynch. The gong sounded again, followed by the roar of the released torrent.

From up the channel there came a man’s hoarse shout and the piercing scream of a woman.

“Shut off the water, you damned idiot!” shouted Inspector Little.

But Lynch, in the excitement, had completely lost his wits. He didn’t seem able to locate the button again.

The inspector sprang back and shoved the detective out of the way while he reached for the projecting match in the hole himself.

Louis Hammond, at the edge of the raging torrent, stood transfixed, terrified at what he saw being flung down toward him on the crest of the maddened tide.