“Up with the panels! For your lives!” shouted Captain Sprowl, who had guessed what was about to happen the minute the interpreter opened his mouth.

It was this that saved them from the flying hail of spears and darts. As the grizzled seaman shouted his warning, they ducked down simultaneously and Tom pulled the levers that ought to have sent the panels into place, instantly converting the flying auto into an impregnable fortress. But it was just at this critical moment that an unexpected hitch occurred.

The panels refused to move!

“Up with them, quick!” roared the captain.

“Hurry!” cried Mr. Chadwick.

“I—I can’t make them work!” panted Tom, struggling with the levers, “they’re stuck or something.”

“Great dolphins!” groaned the captain. “It’s all up with us then.”

Before Jack had time to inflate the already well-filled gas-bag sufficiently to rise, a wave of humanity broke over the side of the machine. There was no time to snatch up the rifles, hardly an instant in which even to raise their hands. Within ten seconds from the time the first spear whizzed through the air above the adventurers, crouching low in their craft, they were prisoners of Chekla’s tribe.

Here was a fine ending to all their hopes! From the yells and shouts that rose about them they guessed that they might look for scant mercy at the hands of the Indians, who evidently thought that they had had something to do with the stealing of the idol.

They were hustled out of the machine by a score of hands and marched none too gently toward the central building. As they went, they had the satisfaction of seeing the little stone god that was to have brought them good luck, stripped from the stanchions by some of the red-robed men.

It was held aloft while a low, dismal sort of chant filled the air. Many of the Indians prostrated themselves before the upheld image. Evidently its return was regarded as being a momentous occasion.

“What is going to be done with us?” Captain Sprowl demanded of the red-robed Indian who had acted as interpreter and who, with two of his companions, accompanied the boys and their friends to the central house.

But the interpreter affected not to hear.

“Looks mighty bad,” muttered the captain to Jack, who was alongside him; “in fact, I don’t see how it could be much worse. These fellows were inclined to think that we were all right and some sort of little tin gods ourselves, till they saw that pesky idol. Then it was all off.”

“It was all my fault for putting it there,” lamented Jack bitterly. “Well, it’s proved a fine mascot—I don’t think.”

Nothing more was said, and the prisoners trudged along in silence in the midst of the throng that enveloped them. No attempt was made to offer them any violence, but somehow the very apathy of the crowd appeared more ominous than if they had resorted to active resentment. As Jack thought to himself: “It looks as if they had our fate all cut and dried.”

As if in answer to his unspoken thought were the next words of Captain Sprowl:

“Whatever is going to happen to us, these fellows know before it comes off. But we’ve got to put the best face we can on the matter and show them that Americans ain’t going to be scared out of their seven senses by a bunch of image worshippers.”

Insensibly the doughty little captain threw out his chest and glared about him at the capering Indians that surrounded them.

“I wish I had my hands free; I’d spoil some of your ugly mugs for you,” he grunted.

Suddenly the throng broke into a measured chant. It rose and swelled with hideous lack of harmony to the white men’s ears. But nevertheless the chorused burden of the thing was unpleasantly suggestive. The prisoners found themselves actually glad when they reached the central stone house and were escorted inside by the two red-robed priests and six of the feather-ornamented natives.

Once inside the place, the great doors by which they had entered were closed on the mob outside, shutting off their depressing chant. They noticed that the doors were formed of a sort of white stone of immense thickness but beautifully carved, although what the carvings represented they could not make out. They were hurried along too fast for that.

It was evident, however, that the stone structure was, in part at any rate, a royal residence. Within the stone doors was a circular chamber capped with a dome of really beautiful proportions, considering the fact that the Indians must be ignorant of even the fundamental principles of architecture or geometrical design. In fact, they learned afterward that the stone palace was of extremely ancient origin, the work of some forgotten and highly civilized race, possibly allied to the intellectual Aztecs. Chekla’s tribe had simply found the place there and built up a village around it.

The domed central chamber was furnished with mats and hung with skins and spears, and the walls were ornamented with crude carvings. It was without windows, being lighted by means of openings in the stones set in regular rotation around the base of the dome. At each side, however, was a low doorway, hung with curtains of some sort of plaited grass. Through one of these they were escorted and found themselves in a passage, at the other end of which was another door.

They passed through this and entered a rock-walled chamber absolutely bare of any sort of furniture or fittings. It had a damp, musty sort of odor attaching to it and this, together with the fact that the passage had inclined downward rather steeply, led them to believe that they must be underground.

But wherever they were, it was evident that they had reached their destination. The red-robe who had acted as interpreter spoke to his assistants and they released the captives. Then they backed out slowly, menacing the white men with their spears in case they might attempt to “rush” them.

They reached the doorway, and still holding their spears in threatening postures, backed out. The red-robed man was the last to go. As he vanished a stone door poised on unseen hinges swung noiselessly into place. The prisoners exchanged despairing glances. Under what conditions would that door be reopened? Would it be when they were led forth to death or torture?

A search of the rocky chamber, made as a forlorn hope, without any idea of finding a place by which an escape might be effected, showed that, with the exception of the door and a sort of lattice-work opening in the ceiling through which light and air came, the place was solidly walled in.

“Well, I don’t see what we can do except possess our souls in patience and sit down and wait for what’s to come,” declared Captain Sprowl, when the examination had been concluded.

“There’s nothing else to be done,” agreed Mr. Chadwick despondently.

“Chentlemen,” spoke up Professor Von Dinkelspeil, “dis is mein fauldt. I cannodt ask you to forgive me, budt I vould radder haf nefer seen der country dan dat dis shouldt have happened.”

“It’s not your fault, professor,” declared Mr. Chadwick warmly; “we undertook this expedition knowing what risks we were facing, and we must meet our fates like men.”

“What do you think will become of us?” asked Tom in a doleful tone.

“I can form no idea,” rejoined his uncle. “I hardly think that they will dare to proceed too far. This country is not absolutely inaccessible and Judkins, in the event of the worst happening, would take the news to the outer world and we should be avenged.”

“A lot of good that would do us,” snorted Dick Donovan.

“It’s your own fault that you’re here, anyhow,” snapped Tom irritably.

“True enough,” admitted Dick, “I didn’t mean to complain. I can face anything we’ve got to go through as an American should. At least, I hope so.”

Conversation languished after this. They sat leaning against the walls of the place, each busied with his own thoughts. But the undaunted professor was busy examining the walls. In his scientific ardor in gazing at the many queer scrawlings with which they were covered, he appeared to have forgotten everything. Suddenly he gave utterance to a sharp exclamation.

“Himmel! Vos is dis?”

And then the next minute his voice rang out sharply, trembling with suppressed excitement:

“Chentlemen! Look! I haf foundt idt!”

For one joyous instant they thought that he had discovered a way of escape. But they soon saw that it was one of the wall carvings that had attracted his attention and caused his outburst.

“What is it? Nothing but a hunting scene, ain’t it?” asked the captain, who was nearest to the excitable German.

“Precious badly done, too,” he added. “I know kids at home in Maine, eleven-year-old kids, that could do better than that.”

“Ach! Dot is nodt idt!” exclaimed the professor impatiently. “Idt is nodt a vurk of arts dot I know. Budt idt iss something bedder—idt iss a picture of der hunting of der Megatherium!”