"He's giving them the old fable with a new twist," Mike told Biff. "How the ancient Aztecs found a speaking statue of Mexitli in a mountain cave-this cave, no less-and how it guided them to a place where they saw an eagle perched on a cactus with a snake in its beak."

Biff nodded. That was the famous legend of how the Aztecs built their great capital of Tenocht.i.tlan, which later became the site of modern Mexico City.

"But listen to this," continued Mike, as Tizoc paused. "This faker is telling them how hundreds of years ago, he came here, as Emperor of the Aztecs, wearing this same mask and robe, to represent Huit-zilopochtli, or Mexitli, as he prefers to call him."

"Which the real Tizoc probably did," reminded Biff, "so he is telling them a pretty solid story."

"But he's overdoing it," insisted Mike. "He claims that he brought the talking idol of Mexitli with him and that after all these years, it will speak to them as it did to him, so they can live for centuries as Tizoc has. Now, how can he hope to get away with that?"

Mike's question was promptly answered. Tizoc wasn't banking on mere hope. He had some real tricks up the sleeves of his golden robe. He waved his arms with a spreading motion, and the Eagle Knights moved wide apart. Then Tizoc himself stepped backward and slightly to one side. In the manner of a master show- 136 .

man, he gestured to the innermost portion of the cavern.

Perched on a rocky pedestal was the stone statue that Tizoc had mentioned. As he approached it, the likeness between the stone figure of Mexitli and Tizoc, the masquerader, proved striking indeed. The stone body, though small and rough-hewn, resembled a robed figure, which was sufficient. The important part was the face. Of natural size, perfectly proportioned, its features were identical with Tizoc's mask.

Automatically, Biff phrased it: "Tizoc to a T!"

"Or the other way about," declared Mike. "The mask that Tizoc is wearing looks as though it was pressed from the statue's face. The mask came from Aztec times; maybe the statue is authentic, too!"

Further whispers were drowned by a booming voice that literally filled the cavern with its heavy tone. It seemed actually to come from the statue of Mexitli as Tizoc stood complacently by. Biff caught the meaning of those thunderous words. The voice of Mexitli was saying: "I, Mexitli, order you to follow Tizoc!"

As the echoes died, the villagers babbled their willingness to obey. Now, Tizoc was giving orders of his own and sombreros bobbed above nodding heads, Mike grabbed BifFs arm and urged him to the outer cavern.

"Tizoc is telling them to go and meet the pack TRAPPED! 137.

train," Mike explained. "They are to bring some of the mules here and help unload them. We had better wait here."

Mike drew Biff into a darkened patch, away from a high fissure where daylight trickled through. By then, Tizoc's new followers were thronging out from the inner cavern.

"Let them go ahead," advised Mike. "Give them a good start to the trail, then we can move along."

The plan was perfect. After the villagers had moved out to the narrow mountain ledge, Biff and Mike kept watching the opening from the inner cavern in case Tizoc should appear there. But there was no sign of the masquerader nor any of his armored knights.

"It's clear now," decided Biff. "Let's go."

They went, but not far. Before they were halfway to the outer opening, figures grew from the rough floor of the fissured cabin and closed in with long, leaping strides. More Eagle Knights, a half a dozen of them, who had been lurking here all this time, watching all persons who came in and out!

The bird-helmeted attackers flung aside their war clubs and their spears and swarmed over Biff and Mike in an overwhelming force, suppressing the astonished, outmatched boys in swift, bare-handed style.

From the opening of the inner cavern came a harsh, metallic chuckle. That tone was Tizoc's.

CHAPTER XVI.

Over the Brink TIZOC presented a truly formidable figure as he again stood beside the squatty statue of Mexitli, studying the prisoners who had been dragged before him.

The Eagle Knights had done a swift, capable job of binding Mike and Biff hand and foot, with their arms trussed behind them. They were so tightly tied that it was impossible to move a muscle without pain.

The boys could never hope to slip those intricate knots that Tizoc's followers had tied with all the craft and skill that they had inherited through many generations.

From the faces of the bird-helmeted crew, Biff was sure that all were villagers or natives from surrounding areas who had been hand-picked and sworn to secrecy in Tizoc's service. Biff and Mike themselves had seen exactly how it worked; that was why they were here and in this predicament. 138 OVER THE BRINK 139.

These Eagle Knights must have been among the first to join up with Tizoc. As such, they had earned promotion to their present status. Now they stood by approvingly, almost expectantly, as Tizoc drew the obsidian knife from beneath his golden costume and brandished the red-bladed weapon toward the prisoners.

It was like the scene at Judge Arista's, but here Tizoc was in his own domain. There, he had been forced to fight his way clear. Here, he could bide his time where knife strokes were concerned. But as Tizoc poised the blade, Biff felt sure that he meant to follow through with a brutal downward slash. Biff closed his eyes, wondering whether he or Mike would be the first victim.

A buzz came from the Eagle Knights. Biff opened his eyes and saw Tizoc lowering the knife with a careless gesture, indicating that he did not intend to strike. Next, he made a pretence of cutting Biff's bonds, after which he turned to Mike and went through the same pantomime.

Biff recalled crude pictures that he had seen portraying helpless prisoners trying to fight off Eagle Knights. Often, the Aztec warriors had played that cat-and-mouse game with their victims. Now, Tizoc was going through the pretence of turning over the prisoners to the Eagle Knights, who raised their spiked war clubs in approval.

Then, as a final gesture, Tizoc raised the knife again 140 .

and stretched it toward the Mexitli statue. He brought his hand downward, slid the knife beneath his robe, as if replacing a sword in its scabbard. The act was over, and its significance was plain.

Tizoc intended to let the prisoners live until he had a.s.sembled all his followers, rather than just these few. Biff and Mike already knew how long that would be; until late afternoon, when they returned with the loaded mules from the incoming pack train. That decision made, Tizoc delegated two of the Eagle Knights to watch the prisoners. He then strode off into a side cavern, followed by the remaining knights.

The guarding pair dumped Biff at one side of the domed cavern and Mike at the other. That left the prisoners facing each other, some fifty feet apart, with the Mexitli statue at the rear wall, halfway between. In the dim, uncertain light, the statue's partly open mouth seemed at times to form an ugly, downward leer, as though enjoying the plight of the prisoners.

And a hopeless plight it was, considering the tightness of their bonds and the fact that two armed Eagle Knights were pacing in between, keeping almost constant watch. An hour or more pa.s.sed; then, the two guards held a conference and decided that only one was needed to keep watch. One left the domed cavern; the other took up a station at the entrance, where he sat facing the statue and could eye the prisoners by simply turning his head either way.

By the end of another hour, Biff's arms, legs, and OVER THE BRINK 141.

body had become so numb that they no longer hurt. From Mike's fixed position, he evidently felt the same. Then came the first break in the monotony, a low, distant buzzing sound that rose to a steady drone.

It struck Biff that this was another of Tizoc's tricks, having to do with the fact that Huitzilopochtli had originally been the hummingbird wizard, before becoming the Aztec War G.o.d. Oddly, the sound did seem to come from the Mexitli statue, but as it faded, Biff realized that it was an outside noise that had come through from the outer cavern.

That meant it must be the plane coming in from Mexico City, probably bringing Mr. Brewster with it. Now, Biff wished grimly that he had left a note as he originally intended. The only other chance was that Professor Bortha would come up to his room at the Hotel Pico and find the torn slips that Biff had left with the recording machine; but that was most unlikely.

Soon afterward, one Eagle Knight returned to relieve the other, but there was no relief for Biff or Mike. They just sat and suffered in silence, with no way of guessing how long, until Biff noticed that the new guard was beginning to nod as he sat at his post in the doorway.

It was after siesta time, and even in this cool cavern, the man was becoming drowsy from mere habit. Several times, Biff watched him try to rouse himself from his nap. Then, with a glance at the prisoners, 142 .

the Eagle Knight gave a shrug and settled back to sleep, quite positive that the victims could not escape.

Biff tugged at the ropes only to bring pain to his already numbed muscles. Half aloud, he muttered: "It's now or never." Then, hopelessly he decided it would be never. He leaned his head back against the rough wall and a whisper crept into his ears: "Was that you, Biff?"

It could only be Mike, but Biff stared incredulously. Maybe the long ordeal was making him hear things. Then he whispered back, "Yes, can you hear me?" The result was another response from Mike. Then they were talking back and forth in the lowest of tones, even though they were so far apart.

Their whispers were carrying up the curved dome and down the other wall. The cavern was actually a "whispering gallery" and something of an echo chamber. That explained the vast voice that had seemingly come from the Mexitli statue. Tizoc had supplied it by standing alongside and speaking in a heavy, booming tone that had been magnified still further. He hadn't needed to be a good ventriloquist; the mask had hidden his moving lips.

"We've got to get out of here, while we still have time, Mike," Biff whispered urgently.

"Yes, but how?" Mike whispered back. "I'm tied so tight, I can't even move-ouch!"

"What happened, Mike?"

OVER THE BRINK 143.

"It was like a jab in the back-a muscle, I guess- ouch-there it comes again-I don't know what it is-"

As luck had it, Biff had tilted his head, to send his whispers better. His eye caught a glint high in the wall of the cave. He looked lower and thought he saw another sparkle, though the light there was less. In the lowest of whispers, Biff suggested: "Work your hands up your back, Mike, but carefully. You may get a cut from the sharp edge you find there."

Biff waited; then Mike's exclamation came: "I've got it. Say, it's like a knife blade. It's the thing that was jabbing me. It's set solid in the rock."

"A chunk of volcanic gla.s.s," Biff said. "The walls are loaded with it. Get your wrists over to it and try to cut the rope. But be careful!"

"I'll say I will!"

Mike, too, had seen the blade of Tizoc's obsidian knife and the jagged edges set in the war clubs carried by the Eagle Knights. Biff also was careful as he shifted position as much as he could, hoping that he would have Mike's luck. A sudden jab caught him in the right elbow. That was it. Now they both were working at their wrist bonds.

It was touch and go, dragging the ropes against those gla.s.sy points and at the same time avoiding cuts that might prove serious. But they managed it, Mike 144 .

whispering first that he was free and Biff coming up with similar news a few minutes later.

By then, Mike was working on his ankle ropes, having managed to shift and draw them across the sharp projections. Biff copied the system, so at no time did they bring their hands in sight, even if the guard had been awake enough to notice. Then, both boys were free. After an exchange of whispers, they rose unsteadily, crept toward the guard as well as they could and finally flattened him with a headlong drive.

The bird-shaped helmet went bouncing across the floor and next, the guard's head thumped the lava. That ended the brief struggle. As the Eagle Knight lay senseless, they bound him with their ropes and gagged him with some of his own feathered tr.i.m.m.i.n.gs. Then, instead of starting straight out as they had before, Biff and Mike moved into one of the side caverns, hoping to avoid any other guards.

There, in the half-darkness they came across great stacks of solidly packed boxes. Biff thought at first they might be filled with silver, but when he and Mike managed to move a few of them, he decided they weren't heavy enough.

"They must be supplies of some sort," declared Biff, "that came in by pack train."

"Supplies of what?" queried Mike. "I'd like to pry into one of those boxes and find out."

Mike was trying it, with a sliver of rock that he OVER THE BRINK 145.

found on the floor, when Biff gripped him and said, ' "Listen."

They could hear sounds from a corner beyond the stacked boxes. With one accord they moved the other way, found still more stacks blocking them, but finally picked an opening to the outer cavern. It was just in time, for above the dozens of stacked boxes, they saw the helmets of three Eagle Knights moving into the inner cavern where their comrade lay bound.

Then the boys were outside. The daylight seemed blinding, though the afternoon was growing fairly late. Mike could hear the shouts of Eagle Knights from back in the cavern. He urged Biff to hurry along the ledge that formed the only route back to the trail. But at the first turn, Biff drew back, saying: "Look!"

The rock-hewn path was blocked by figures that were coming the other way, men in baggy white, leading burros behind them. Tizoc's new crew had joined with his older followers, and they were bringing in another shipment of boxes from the arriving pack train.

To Biff, there seemed no escape, but Mike knew a way out, for he had thought of this very situation earlier. He grabbed Biff by the arm and dragged him toward the ledge rim.

"We've got to go down the cliff!" exclaimed Mike. "It's our only chance-and there's no time to lose!"

CHAPTER XVII.

Out of the Sky THEY were over the brink and a dozen feet down before Biff realized how harrowing this descent was going to be. Mike had purposely chosen a spot where the cliff slanted slightly outward and sharp clefts in the rock offered natural footholds.

But as they reached the bulge, Biff glanced over his left shoulder, expecting to find another jutting rock. Instead, he saw a sheer drop. Momentarily, the height made him dizzy, but he came out of it by clinging tightly to the bulging rock and looking over to his right, toward Mike.

Mike was as cool as he had been that day when they went down the mountain trail. He quickly sensed Biff's problem.

"Over this way, Biff," Mike told him. "It is like an escalera, just as I said." 146 OUT OF THE SKY 147.

Mike had found a broad fissure that zigzagged . downward past the bulge. He worked down it first and Biff followed, feeling his way with one foot, then the other, taking Mike's advice as he did.

"Left foot farther out, Biff. That's it. Don't look down. Keep looking up-always up."

That last was the best advice of all. It kept Biff's mind off the dangers below. It also helped where dangers above were concerned. Their zigzag course took them beneath the bulge that had worried Biff earlier. In so doing, it cut off any view from the ledge, if Tizoc's followers happened to suspect that the escaping prisoners had gone this way.

There were clumps of vegetation in the cliff, growing from patches of earth. Some of the clefts went very deep into the rock, affording good resting spots. At one of these, Biff asked: "What if we come to a bulge and can't work our way down and around it?"

"Then we climb up again," replied Mike, with a grin. "Don't worry, Biff. I've looked at this cliff both ways. I looked up at it the other day; I looked down at it today. I saw what we could do. We are doing it."

Thus encouraged, Biff continued the descent. They were a third of the way down, working almost side by side when Biff caught what he thought was a hissed signal and turned his head Mike's way. Just then, Mike called:

OUT OF THE SKY 149.

"Get out of there, Biff! Quick! Start climbing the 'other way!"

It sounded crazy, for Biff had just planted one foot in a wide crevice where he had felt the crunch of firm, solid earth. But he followed Mike's advice instinctively, and it was well that he did. Biff risked a downward look as he scrambled up the cliff and saw a much closer menace than the rocky ground nearly two hundred feet below.

A big snake had uncoiled close to the spot where Biff had placed his foot. It was striking upward from the crevice, with Biff's leg as its target. Thanks to the slant of the rock, it missed, but as it hissed again Biff heeded its warning. He not only scrambled upward, he sidled along the cliff, digging his toes and fingers into every niche.

At one spot, Biff grabbed what he thought was a writhing snake and he fairly flung the thing away from him, only to realize that it was a vine growing from a dirt-filled pocket in the rock. Half a minute later, he was clinging to an almost perpendicular portion of the cliff, but he was well out of danger, or so he thought.

Then, slowly, grimly, the true situation dawned. In his mad scramble, in letting go of that handy vine, Biff had reached a place where he had sufficient hold to cling, but not enough to give him the needed takeoff to any other vantage point within his reach.

Every way that he tried to stretch, the distance was 150 .

too great. When he probed with one foot, then the other, hoping to find some crevice below, his toes encountered only sheer, smooth rock. Each effort threw more strain on his fingers; his toes, too, were finding it difficult to regain their former holds. He was wondering how long he could hang on, when he heard Mike's voice, encouragingly close.

"Easy, Biff. Don't go kicking around like that. Can't you find a foothold anywhere?"

"Not even in another snake pit, Mike."

"Hold tight then, while I look it over."

Mike looked it over, working downward, upward, and finally to a level where his shoulders were just about beside Biff's knees. Steadily, Mike said: "You've got to do exactly as I tell you, Biff. There is a ledge, a nice one, about six feet below you. The only way you can reach it is to slide straight down-"

"It's no good, Mike," Biff broke in. "I'll go outward on the way."