“Hey, what are you waiting for?” Lang called sharply.

“These kids want their arms loose,” the guardian answered.

“Tell ’em to slide with their heels—”

“I won’t. I gotta get over, haven’t I!” The fellow’s teeth chattered and the weapon he held wavered in his trembling hand.

“Send one along. I’ll meet him,” Mills decided.

“All right, get on, if you kick that thing I’m goin’ ter pump you full of lead, and your buddy too, see.” The man poked his white face into Jim’s.

“Surely, it’s quite clear.” Jim stepped forward, straddled the log, inched himself along with the greatest care, but his heart was in his throat as bits were knocked off. He had gone almost half the distance when he saw Mills throw himself full length from the other side, and stretch out his hands.

“Bend forward.” Jim did and Mills clutched his collar firmly, then wriggled back. Half an hour later Bob was over safely, but when he stood up a great hunk of the log fell away.

“Listen,” he cried, “that will never hold another man, and that chap over there is scared stiff. Loosen my arms, or Jim’s, then we can get him with the lariat and if he starts to fall, haul him up. He’ll never make it—he’s heavier than we are.”

“Wait up, over there,” Lang shouted.

“What for?” he snarled suspiciously. “I aint hanging round here.”

“Wait up till we get a rope—” Just then a strange wailing sound came from behind the man and he glanced fearfully over his shoulder. Mills had started to remove Bob’s rope, but his fingers were clumsy and he fumbled nervously.

“Hold that light closer,” he growled to the chap who had the flash. The rays were directed on the knot while the rest stood impatiently watching, and after a moment one of the men laughed; it sounded like a cackle.

“Those kids—”

“What you waiting for?” called the man across the gully.

“Keep your shirt on, we’re going to throw the rope—”

“Woo-oo-o-oh,” came the weird sound again, only louder. It seemed to be getting closer quickly, rose from a deep moan to a shrill wail that filled the narrow passage, and the man who was holding the flash let it fall from his cold fingers.

“I’ll hold it—”

“I’m coming—” roared the one on the other side. He glanced over his shoulder a second time, then the sound came nearer, louder, and more terrible. With a shriek he flung himself astride the log, his body flat, his arms and legs kicking furiously as he shoved frantically forward, disregarding the danger of the undertaking.

“Be careful,” yelled Jim as he watched the fellow, whose limbs were striking out like a floundering swimmer, sending a shower of rotten timber to the depths below. “Take it easy, you won’t make any headway.”

“Look out—” Mills stopped his futile efforts to get the rope, Lang turned the rays of the light on the log, while one of the other men stood astride the end trying to swing a long vine to the hands of their comrade. He bent forward and threw the long twining end, but the chap was not looking at him, the bit of tendril brushed his cheek; and with a howl of panic he twisted about desperately.

“Catch it,” Lang shouted.

“Get a hold,” Mills added. But the man was too terrified to understand. With a wild lunge he threw himself on the weakest part of the log, clawed with both hands, sending a shower of chips into the abyss and at the same time, the awful unearthly cry came again. Another panic-stricken lunge, the log creaked dismally, parted in the middle, and dropped its burden to the depths. The fellow who was astride the end was nearly taken with it, but Mills caught and hauled him to safety.

“If he’d waited for the rope he could have been saved,” Bob said softly, and there was genuine regret in his tone. It was a tragic situation, standing tied helplessly while a fellow human fell to his death.

“Something’s back there—”

“I believe that is only wind,” Jim declared.

“Wind, how do you make that out?”

“Since the air purified, either there is a high wind outside or something happened to let in a good breeze. It played on those tight streamers and vines like a harp—”

“Queer harp,” Mills muttered with a shiver.

“Just the same, that’s all it is, I’m sure. If you have been around the Andes much, you’ve heard something like it before—”

“Well, I haven’t been, and I’m getting out now fast as I can, see?”

“Come on,” Lang ordered, and putting Jim in front to lead the way, they started forward again, but now there were only four members of the gang with the Buddies.

The way was wide enough so that they could go side by side, and although their shoulders touched as they proceeded, they did not exchange a word, for Mills and Lang were right behind them. After all, it did not make much difference, but there was really nothing to say. The queer noise was repeated at intervals, but although it was terrifying enough, the men grew less fearful of it and seemed to accept Austin’s explanation as to its origin. The boy had thought it was the wind when he first heard it, but had kept silent partly because his opinion was not asked and partly because he felt that the bandits deserved a good scare. He reasoned that if they were frightened they might be less vicious in their dealings with their captives, but when he saw the havoc it was creating he endeavored to reassure them. However, if any of them appreciated his assistance no sign was made of the fact, and the pair were urged to proceed ahead.

“If there is danger they figure we’ll get it first,” Bob whispered, and Jim nodded.

“These kids are terribly slow,” snapped a man in the rear. “We want to get out of this place.”

“Sure, Lang, hurry ’em up,” said the other nervously. “This hole is spooky. Why in blazes didn’t you find out what was in it?”

“Shut up, I’m managing this,” Lang snapped back.

“If them kids has a pull with the Indians they’ll get us through,” Mills called, and then the Buddies understood that the leaders expected to share any protection that the presence of the “Don’s little pets” as he called them, might be to the gang. This was a phase neither of the boys had thought of, and now they exchanged swift glances.

“We’re going along nice now; when Red was leading it was tough,” added Lang, then went on to Bob, who had stared back. “Your help is appreciated a lot you can see, but any funny business and you’ll wish you had dropped over off the log with Red.”

“You said we’d be out of here in a few minutes. It’s getting worse instead of better,” the rear man grumbled.

“Yeh, it’s thick and hot. My light won’t last forever. Got any more batteries?”

“Yes.” They paused to fix the flash, and Lang swore at them roundly. “I told you to have new lights, and to pack spare fillers. What did you mean by coming half ready—”

“Aw shut up, my light was brand new, but Red carried the extras,” the other admitted reluctantly. At that Lang and Mills ripped out a string of oaths.

“Haul in,” one snapped finally. “Didn’t you tell us to divide the stuff—well, Red took the batteries—that’s that—”

“And we’ll likely have to crawl out of this in the dark, land somewhere in the forest, and who knows how we’ll get back to the machines?” Mills thundered. “What are you carrying?”

“Grub,” came the answer.

“Well, let’s stop and eat. We can make better time when we are not so empty,” Lang proposed. “Pass it along.” He and Lang sat down as best they could in the narrow quarters with only the smallest light to pierce the gloom which surrounded them. The Buddies also let their feet slide from under them and were grateful for the opportunity to rest. The two men who brought up the rear showed no such disposition, but stepped forward over the other’s legs.

“Here,” the last one muttered, dropping what looked like a paper bag into Lang’s lap, then went on quickly. The leader started to open the container, then glanced up with a scowl.

“Where’s the rest of the stuff?” he demanded.

“Think we been traveling for hours with nothing in our stomachs?” came the answer.

“What’s left?” Mills snapped, grabbing the bag.

“Aw there’s a couple of sandwiches en a hard boiled egg—”

Mills sprang to his feet but the pair jumped out of his way quickly.

“Come on, Mills, eat what there is,” Lang called, so the tall man returned, and the two soon devoured the frugal repast. Not a bite was offered to the Buddies whose food had been left in the plane on the hill, and whose stomachs were clamoring furiously. Presently the meal was finished to the last crumb, then the leaders rose to their feet. They did haul their companions up so they could stand, then without a word, gave them a shove forward.

Slowly and painfully the four proceeded. The Flying Buddies’ feet hurt with every step, and their tired bodies wavered from side to side as they went on and on. By that time they were going through what appeared to be a grassy section of the forest. The passage wound among huge trees, over piles of fallen timber, then, suddenly from ahead, they heard a wild shriek of terror, followed by a series of shrill earsplitting screams.

“Good Heavens, what they got into?” Lang panted.

“Get on,” Mills urged. He slipped his hand under Bob’s arm and helped him forward, while Jim and Lang stumbled along as quickly as possible. Presently they came to a section where piles of rotten vegetation lined both sides of the route, and by the dim light Lang cast ahead, they made out one body lying still, while the other battled furiously with some hissing object that lashed and struck with thunderous blows.

“Snakes,” Bob whispered.

They saw a second man borne down to the ground and after a convulsive struggle for a moment, he too lay still. The four stopped horrified in their tracks. For minutes they stood staring too paralyzed to go forward or back, then Bob saw the great snakes slide off to one side and disappear under the debris.

“Come on, walk carefully and be quick,” he panted, and started to run, forcing his aching feet to carry him on. Passing the spot they could see that their two companions had probably stumbled over the reptiles, angered them to instant attack, and were utterly defenseless against the poisonous brutes.

Hardly daring to breathe lest the snakes come out again, the four tiptoed forward, but in each hand of the leaders were small, deadly guns ready to destroy the snakes if they showed their heads. Beads of perspiration stood out on the four faces, and for the first time since they started, Lang neglected to keep an eye on the captives. Half an hour later the place was well behind them and they were traversing a sandy way which took them to a stream.

“I’ve got to have a drink,” Jim declared, and without further ado, he dropped flat and buried his face in the cool depths. Caldwell followed his example, and soon Mills and Lang were also stretched full length and drinking deeply.

“Maybe it’s poison but I don’t care,” Mills muttered.

“Better not take too much at a time,” Jim warned. “Drink a little, then rest and drink some more.” The suggestion was carried out. Several times they did it, then, with a sigh, Mills rolled over and closed his eyes.

“Hey, Mills, what’s the matter with you?” Lang shook him roughly by the shoulder.

“Dog tired,” he answered. “I’m going to sleep.”

“Sure that water didn’t knock you out?” Lang persisted fearfully.

“It’s grand water. I’m going to sleep beside it, have some more when I wake up, then go on,” he said heavily.

“So’m I,” Lang declared, but he took the precaution to tie the ends of the ropes which bound the arms of the Flying Buddies to separate trees so that they could not help each other to get away, then he, too, closed his eyes. Jim watched him several minutes, the smallest flash light in one hand, a gun in the other. The boy thought that he could keep awake and that he and his buddy could make some plan, but his own lids grew heavy and presently all of them were sound asleep, in spite of the terrors which surrounded them.

It seemed to Austin as if he had barely closed his eyes when he felt something brush gently against his cheek and instantly he was wide awake. The first thing he noticed was the dim light sending its feeble ray into the darkness, cutting a faint glow which made the rest of the place blacker. The boy tried to brush his face on his shoulder, which ached woefully but as far as he could see or feel there was nothing near him. Mills snored melodiously, while the deep breathing of the other two could be heard plainly, but no other sound broke the death-like stillness of the ancient passage.

“Reckon I’m so tired and sore I’m imagining things,” he told himself, then glanced across to where Caldwell was huddled like himself close to a tree. The boy closed his eyes again, but a moment later they were wide open, so he shifted his position quietly and began to try to make a plan which would help them get away. Carefully he moved his face about the ground hoping to discover a sharp stone upon which he might rub the rope until it was cut in two, but he found nothing, then he began to hitch and wriggle his body. It was a mighty painful process for his arms were swollen and he dared not make a sound. At last, after a grim struggle, he had the satisfaction of feeling the lariat shove upward toward his shoulders. If he could get it as high as his neck he would be free. With a heart pounding hopefully he persisted. Twice he had to stop precious minutes for Lang stirred in his sleep and the lad feared he would wake and discover what he was doing. Nearly an hour passed and at last the rope was slipped above his shoulders; a moment more and he was out of it.

All this while his mind was working like a trip hammer planning what to do when he got loose. The first thing would be to take possession of Lang’s gun. With that in his pocket he might force the men to release Bob in case he wasn’t able to do it himself. His step-brother was the other side of Mills and whether that journey could be made safely was another matter. With the weapon in his pocket at last, Jim devoted the next few minutes to rubbing his sore arms, for he knew that in their present condition he could never hold the gun, much less fire it effectively. In due time his arms were relieved, then he wished that he had on soft-soled shoes, but he managed to get to his feet, take possession of the flash-light, and at last, assured that his activities were unobserved, he made his way to Bob’s side, bending over him carefully. Instantly the young fellow looked up in startled surprise, then Jim grinned, for Bob was industriously chewing his own rope and had managed to get half way through it. A moment more and it was cut and he too was free, while Jim took Mills’ gun, which he gave to the younger boy.

“This place is lighter,” Bob whispered, and Jim glanced around. He was greatly puzzled, for as far as he could see there was no explanation to the fact. No one seemed to be coming with a light and certainly no new opening had been made into the passage, but the glow was unmistakable and it filled the place. Gently Jim rubbed his step-brother’s body, and presently, Bob stood up, but just then Mills stirred uneasily, so the Sky Buddies sat down again quickly and quietly. They watched through half closed eyes, and although Mills tossed restlessly, he finally lay still and again his melodious snore broke the silence.

“Grand uproar,” Bob grinned. Then he got busy knotting his rope, and looped it on his arm. “We’ll do a bit of tying,” he announced.

“Wait,” Jim whispered, then he motioned his pal to move further from the sleepers. They stopped several feet away. “I have an idea. Suppose we lay the ropes so when they sit up we’ll have them hog-tied with a loop, and as soon as we’re ready we’ll wake them and make them get moving.”

“Good idea,” Bob agreed. “They had something to eat and some sleep, and we didn’t. Got any of those pellets Ynilea gave you—”

“You bet, I forgot all about them.” Jim fished the tiny container of food pellets they had been given at the laboratory, and the pair soon had some in their mouths.

“Look,” Bob pointed along the way they had come and to their astonishment they saw a young girl carrying a basket on her head. She came toward them as if unconscious of their presence, her sandaled feet hardly touching the floor of the passage, her body covered with a whole tiger-skin. Behind her walked a woman, then several men came forward single file. Every one of them carried boxes, some opened and others closed, while a few older men carried bags woven of grass. The band came closer and closer until the girl passed directly in front of the Buddies. She never turned her dark eyes but went on, stepping over the sleepers.

“Natives,” Jim whispered.

Both of them completely forgot to lay the lariats, which were looped in their left hands, then suddenly an exclamation made them whirl about. Lang was sitting up rubbing his eyes stupidly, while Mills too was staring wide awake.