Either the Red was lucky, or his reactions were quick. He had somehow rolled clear of the struggling horse as Lupe leaped from behind a boulder, knife out and ready. To the eyes of the Apaches the helmeted man lay easy prey to Lupe's attack. Nor did he raise an arm to defend himself, though one hand lay free across the plate on his chest.

But the young Apache stumbled, rebounding back as if he had run into an unseen wall—when his knife was still six inches away from the other. Lupe cried out, shook under a second impact as the Red fired an automatic with his other hand.

Travis dropped his bow, returned to the most primitive weapon of all. His hand closed around a stone and he hurled the fist-sized oval straight at the helmet so clearly outlined against the rocks below.

But even as Lupe's knife had never touched flesh, so was the rock deflected; the Red was covered by some protective field. This was certainly nothing the Apaches had seen before. Nolan's whistle summoned them to draw back.

The Red fired again, the sharp bark of the hand gun harsh and loud. He did not have any real target, for with the exception of Lupe the Apaches had gone to earth. Between the rocks the Red was struggling to his feet, but he moved slowly, favoring his side and one leg; he had not come totally unharmed from his tumble with the pony.

An armed enemy who could not be touched—one who knew there were more than outlaws in this region. The Red leader was far more of a threat to the Apaches now than he had ever been. He must not be allowed to escape.

He was holstering his gun, moving along with one hand against the rocks to steady himself, trying to reach one of the ponies that stood with trailing reins beside the inert Tatars.

But when the enemy reached the far side of that rock he would have to sacrifice either his steadying hold, or his touch on the chest plate where his other hand rested. Would he, then, for an instant be vulnerable?

The pony!

Travis put an arrow on bow cord and shot. Not at the Red, who had released his hold of the rock, preferring to totter instead of lose control of the chest plate—but into the air straight before the nose of the mount.

The pony neighed wildly, tried to turn, and its shoulder caught the free, groping hand of the Red and spun the man around and back, so that he flung up both hands in an effort to ward himself off the rocks. Then the pony stampeded down the break, its companions catching the same fever, trailing in a mad dash which kept the Red hard against the boulders.

He continued to stand there until the horses, save for the wounded one still kicking fruitlessly, were gone. Travis felt a sense of reprieve. They might not be able to get at the Red, but he was hurt and afoot, two strikes which might yet reduce him to a condition the Apaches could handle.

Apparently the other was also aware of that, for now he pushed out from the rocks and stumbled along after the ponies. But he went only a step or two. Then, settling back once more against a convenient boulder, he began to work at the plate on his chest.

Nolan appeared noiselessly beside Travis. "What does he do?" His lips were very close to the younger man's ear, his voice hardly more than a breath.

Travis shook his head slightly. The Red's actions were a complete mystery. Unless, now disabled and afoot, he was trying to summon aid. Though there was no landing place for a helicopter here.

Now was the time to try and reach Lupe. Travis had seen a slight movement in the fallen Apache's hand, the first indication that the enemy's shot had not been as fatal as it had looked. He touched Nolan's arm, pointed to Lupe; and then, discarding his bow and quiver beside the war leader, he stripped for action. There was cover down to the wounded Apache which would aid him. He must pass one of the Tatars on the way, but none of the tribesmen had shown any signs of life since they had fallen from their saddles at the first attack.

With infinite care, Travis lowered himself into a narrow passage, took a lizard's way between brush and boulder, pausing only when he reached the Tatar for a quick check on the potential enemy.

The lean brown face was half turned, one cheek in the sand, but the slack mouth, the closed eyes were those, Travis believed, of a dead man. By some action of his diabolic machine the Red must have snuffed out his four captives—perhaps in the belief that they were part of the Apache attack.

Travis reached the rock where Lupe lay. He knew that Nolan was watching the Red and would give him warning if he suddenly showed an interest in anything but his machine. The Apache reached out, his hands closing on Lupe's ankles. Beneath his touch, flesh and muscle tensed. Lupe's eyes were open, focused now on Travis. There was a bleeding furrow above his right ear. The Red had tried a difficult head shot, failing in his aim by a mere fraction of an inch.

Lupe made a swift move for which Travis was ready. His grip on the other's body helped to tumble them both around a rock which lay between them and the Red. There was the crack of another shot and dust spurted from the side of the boulder. But they lay together, safe for the present, as Travis was sure the enemy would not risk an open attack on their small fortress.

With Travis' aid Lupe struggled back up to the site where Nolan waited. Jil-Lee was there to make competent examination of the boy's wound.

"Creased," he reported. "A sore head, but no great damage. Perhaps a scar later, warrior!" He gave Lupe an encouraging thump on the shoulder, before plastering an aid pack over the cut.

"Now we go!" Nolan spoke with emphatic decision.

"He saw enough of us to know we are not Tatars."

Nolan's eyes were cold, his mouth grim as he faced Travis.

"And how can we fight him—?"

"There is a wall—a wall you cannot see—about him," Lupe broke in. "When I would strike at him, I could not!"

"A man with invisible protection and a gun," Jil-Lee took up the argument. "How would you deal with him, younger brother?"

"I don't know," Travis admitted. Yet he also believed that if they withdrew, left the Red here to be found by his own people, the enemy would immediately begin an investigation of the southern country. Perhaps, pushed by their need for learning more about the Apaches, they would bring the helicopter in over the mountains. The answer to all Apache dangers, for now, lay in the immediate future of this one man.

"He is hurt, he cannot go far on foot. And even if he calls the 'copter, there is no landing place. He will have to move elsewhere to be picked up." Travis thought aloud, citing the thin handful of points in their favor.

Tsoay nodded toward the rim of the ravine. "Rocks up there and rocks can roll. Start an earthslide...."

Something within Travis balked at that. From the first he had been willing enough to slug it out with the Red, weapon to weapon, man to man. Also, he had wanted to take a captive, not stand over a body. But to use the nature of the country against the enemy, that was the oldest Apache trick of all and one they would have to be forced to employ.

Nolan had already nodded in assent, and Tsoay and Jil-Lee started off. Even if the Red did possess a protective wall device, could it operate in full against a landslide? They all doubted that.

The Apaches reached the cliff rim without exposing themselves to the enemy's fire. The Red still sat there calmly, his back against the rock, his hands busy with his equipment as if he had all the time in the world.

Then suddenly came a scream from more than one throat.

"Dar-u-gar!" The ancient war cry of the Mongol Hordes.

Then over the lip of the other slope rose a wave of men—their curved swords out, a glazed set to their eyes—heading for the Amerindians with utter disregard for any personal safety. Menlik in the lead, his shaman's robe flapping wide below his belt like the wings of some oversized predatory bird. Hulagur ... Jagatai ... men from the outlaws' camp. And they were not striving to destroy their disabled overlord in the vale below, but to wipe out the Apaches!

Only the fact that the Apaches were already sheltered behind the rocks they were laboring to dislodge gave them a precious few moments of grace. There was no time to use their bows. They could only use knives to meet the swords of the Tatars, knives and the fact that they could fight with unclouded minds.

"He has them under control!" Travis pawed at Jil-Lee's shoulder. "Get him—they'll stop!"

He did not wait to see if the other Apache understood. Instead, he threw the full force of his own body against the rock they had made the center stone of their slide. It gave, rolled, carrying with it and before it the rest of the piled rubble. Travis stumbled, fell flat, and then a body thudded down upon him, and he was fighting for his life to keep a blade from his throat. Around him were the shouts and cries of embroiled warriors; then all was silenced by a roar from below.

Glazed eyes in a face only a foot from his own, the twisted, panting mouth sending gusts of breath into his nostrils. Suddenly there was reason back in those eyes, a bewilderment, which became fear ... panic.... The Tatar's body twisted in Travis' hold, striving now not to attack, but to win free. As the Apache loosened his grip the other jerked away, so that for a moment or two they lay gasping, side by side.

Men sat up to look at men. There was a spreading stain down Jil-Lee's side and one of the Tatars sprawled near him, both his hands on his chest, coughing violently.

Menlik clawed at the trunk of a wind-twisted mountain tree, pulled himself to his feet, and stood swaying as might a man long ill and recovering from severe exertion.

Insensibly both sides drew apart, leaving a space between Tatar and Apache. The faces of the Amerindians were grim, those of the Mongols bewildered and then harsh as they eyed their late opponents with dawning reason. What had begun in compulsion for the Tatars might well flare now into rational combat—and from that to a campaign of extermination.

Travis was on his feet. He looked over the lip of the drop. The Red was still in his place down there, a pile of rubble about him. His protection must have failed, for his head was back at an unnatural angle and the dent in his helmet could be easily seen.

"That one is dead—or helpless!" Travis cried out. "Do you still wish to fight for him, Shaman?"

Menlik came away from the tree and walked to the edge of the drop. The others, too, were moving forward. After the shaman looked down he stooped, picked up a small stone, and flung it at the motionless Red. There was a crack of sound. They all saw the tiny spurt of flame, a curl of smoke from the plate on the Red's chest. Not only the man, but his control was finished now.

A wolfish growl and two of the Tatars swung over, started down to the Red. Menlik shouted and they slackened pace.

"We want that," he cried in English. "Perhaps so we can learn—"

"The learning is yours," Jil-Lee replied. "Just as this land is yours, Shaman. But I warn you, from this day do not ride south!"

Menlik turned, the charms on his belt clicking. "So that is the way it is to be, Apache?"

"That is the way it shall be, Tatar! We do not ride to war with allies who may turn their knives against our backs because they are slaves to a machine the enemy controls."

The Tatar's long, slender-fingered hands opened and closed. "You are a wise man, Apache, but sometimes more than wisdom alone is needed——"

"We are wise men, Shaman, let it rest there," Jil-Lee replied somberly.

Already the Apaches were on their way, putting two cliff ridges behind them before they halted to examine and cover their wounds.

"We go." Nolan's chin lifted, indicating the southern route. "Here we do not come again; there is too much witchcraft in this place."

Travis stirred, saw that Jil-Lee was frowning at him.

"Go—?" he repeated.

"Yes, younger brother? You would continue to run with these who are governed by a machine?"

"No. Only, eyes are needed on this side of the mountains."

"Why?" This time Jil-Lee was plainly on the side of the conservatives. "We have now seen this machine at work. It is fortunate that the Red is dead. He will carry no tales of us back to his people as you feared. Thus, if we remain south from now on, we are safe. And this fight between Tatar and Red is none of ours. What do you seek here?"

"I must go again to the place of the towers," Travis answered with the truth. But his friends were facing him with heavy disapproval—now a full row of Deklays.

"Did you not tell us that you felt this strange thing during the night we waited about the camp? What if you become one with these Tatars and are also controlled by the machine? Then you, too, can be made into a weapon against us—your clansmen!" Jil-Lee was almost openly hostile.

Sense was on his side. But in Travis was this other desire of which he was becoming more conscious by the minute. There was a reason for those towers, perhaps a reason important enough for him to discover and run the risk of angering his own people.

"There may be this—" Nolan's voice was remote and cold, "you may already be a piece of this thing, bound to the machines. If so, we do not want you among us."

There it was—an open hostility with more power behind it than Deklay's motiveless disapproval had carried. Travis was troubled. The family, the clan—they were important. If he took the wrong step now and was outlawed from that tight fortress, then as an Apache he would indeed be a lost man. In the past of his people there had been renegades from the tribe—men such as the infamous Apache Kid who had killed and killed again, not only white men but his own people. Wolf men living wolves' lives in the hills. Travis was threatened with that. Yet—up the ladder of civilization, down the ladder—why did this feverish curiosity ride him so cruelly now?

"Listen," Jil-Lee, his side padded with bandages, stepped closer—"and tell me, younger brother, what is it that you seek in these towers?"

"On another world there were secrets of the old ones to be found in such ancient buildings. Here that might also be true."

"And among the secrets of those old ones," Nolan's voice was still harsh—"were those which brought us to this world, is that not so?"

"Did any man drive you, Nolan, or you, Tsoay, or you, Jil-Lee, or any of us, to promise to go beyond the stars? You were told what might be done, and you were eager to try it. You were all volunteers!"

"Save for this voyage when we were told nothing," Jil-Lee answered, cutting straight to the heart of the matter. "Yet, Nolan, I do not believe that it is for more voyage tapes that our younger brother now searches, nor would those do us any good—as our ship will not rise again from here. What is it that you do seek?"

"Knowledge—weapons, maybe. Can we stand against these machines of the Reds? Yet many of the devices they now use are taken from the star ships they have looted through time. To every weapon there is a defense."

Nolan blinked and for the first time a hint of interest touched the mask of his face. "To the bow, the rifle," he said softly, "to the rifle, the machine gun, to the cannon, the big bomb. The defense can be far worse than the first weapon. So you think that in these towers there may be things which shall be to the Reds' machines as the bomb is to the cannon of the Horse Soldiers?"

Travis had an inspiration. "Did not our people lay aside the bow for the rifle when we went up against the Bluecoats?"

"We do not so go up against these Reds!" protested Lupe.

"Not now. But what if they come across the mountains, perhaps driving the Tatars before them to do their fighting—?"

"And you believe that if you find weapons in these towers, you will know how to use them?" Jil-Lee asked. "What will give you that knowledge, younger brother?"

"I do not claim such knowledge," Travis countered. "But this much I do have: Once I studied to be an archaeologist and I have seen other storehouses of these star people. Who else among us can say as much as that?"

"That is the truth," Jil-Lee acknowledged. "Also there is good sense in this seeking out of the tower things. Let the Reds find such first—if they exist at all—and then we may truly be caught in a box canyon with only death at our heels."

"And you would go to these towers now?" Nolan demanded.

"I can cut across country and then rejoin you on the other side of the pass!" The feeling of urgency which had been mounting in Travis was now so demanding that he wanted to race ahead through the wilderness. He was surprised when Jil-Lee put out his palm up as if to warn the younger man.

"Take care, younger brother! This is not a lucky business. And remember, if one goes too far down a wrong trail, there is sometimes no returning—"

"We shall wait on the other side of the pass for one day," Nolan added. "Then—" he shrugged—"where you go will be your own affair."

Travis did not understand that promise of trouble. He was already two steps down his chosen path.

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