As darkness fell they emerged from the gloomy shadows of the divide into a country not unlike that on the American side of the range. Foot-hills covered with scanty growth, and here and there a clump of scraggly cottonwoods intersected by deep gullies, and dry watercourses, were the chief features of the scenery. There was little conversation among the prisoners as they rode along, nor indeed did their position bear discussing. Pete's mind was busy with self-reproach, Jack's with trying to devise some means of escape, Walt Phelps' with what his father would imagine had become of him, and Ralph's and the professor's with real alarm.

"I am a man of considerable reading," muttered the professor gloomily, "yet our present position goes to show that all the book-learning in the world is of no use to men in our position."

"No, I guess Coyote Pete, or Jack Merrill, or Walt Phelps could get us out of this a whole lot quicker than all the classical authors that ever classicked," said Ralph disgustedly.

"I have a fine library at home in the East," said the professor suddenly, and with the air of a man in whose mind a great hope had sprung up. "Do you imagine that this Black Ramon, or whatever his name is, would consider taking that in exchange for our liberty?"

"I'm afraid not," moaned Ralph disconsolately. Yet he could not forbear a smile at the old man's simplicity.

"Library," grunted Pete, who had overheard the professor's remark; "the only kind of library he'd have any use for would be an edition de luxury of a complete issue of greenbacks, bound in calf and horse hide."

"Where can they be taking us?" wondered Jack, as hour after hour passed, and the procession still wound on along the foot of the mountains.

"I've no idea," rejoined Walt Phelps, "I've never been on this side of the range before."

"I was over here oncet," said Pete, "after some strays, but I don't recollect this part of the country."

"How far have we come?" inquired Ralph, more for the sake of saying something than anything else.

"Not more than ten miles, I guess," rejoined Jack; "at night, and among these foothills, distances are very deceptive."

"They ain't so deceptive by half as these greasers," growled Pete. "I can't think of anything I'd rather be doing this instant than pounding the stuffing out of that Jose."

"I can't think why father trusted him," exclaimed Jack.

"Why, that was natural enough," was Pete's rejoinder. "There didn't look to be a chance of his playing us false. If it hadn't been for that fusillade behind us we'd never have lost him. As it is, if only I hadn't lost my head and gone gallivanting off arter the critter, we'd have been safe now."

"Always providing that nothing has happened to father and the others," said Jack sadly.

"Yes. But cheer up, lad. Your father and Bud Wilson are two of the best plainsmen I know. They wouldn't go blundering blindfold into no trap, you can bet."

"I hope not," rejoined Jack, "but that explosion sounded ominous to me. If the bridge is gone they may have gone with it."

"I don't think so," replied Pete. "Sounds travel a long distance in a narrow-walled pass like that, and the sound of a horse going over a bridge can be heard a big ways off at any time. If they'd been on the bridge when the explosion occurred we'd have heard their hoofbeats, anyhow, before they touched off the stuff."

"Well, I'm not going to give up hope till I know," said Jack bravely, though at the moment, had he not known the uselessness of it, he could have given way entirely to his apprehensions.

Suddenly, on rising from a dark gully, they came full in view of a low white building with a tower at one end. The rising moon tipped the structure with silver and showed its every outline plainly, the black shadows sharply contrasted to its white walls and tiled roof.

"The old San Gabriel Mission!" exclaimed Pete, as his eyes fell on the venerable structure. "I thought I began to recognize the lay of the country a way back."

"You've been here before, then?" asked Ralph.

"Yep, after stray horses, as I said. I never knew, though, that Black Ramon and his gang hung out here."

"Well, they evidently do," rejoined Jack; "see, we are headed right for it."

They had begun to take a by-path which lay straight and white in front of them toward the old mission door. As they drew nearer, they could see that in the turret were hung several bells, probably part of a chime brought from Spain in the days when the mission was occupied by Holy Franciscans. It now appeared to be in half ruinous condition, however. Great cracks were in its walls, and several of the bell niches were empty. Here and there tiles had fallen from the roof, and the gaps showed black in the moonlight.

"A splendid specimen of Mission architecture," exclaimed the professor, lifting his hand in admiration, as they drew closer. "Rarely have I seen a finer, and in my younger days I spent some time exploring the Spanish remains in California."

"Well, I reckon it's going to be a splendid specimen of a jail for us," grunted Pete, with a side-long glance at the professor, who had quite forgotten his anxiety in his admiration of the old building.

Pete's words proved correct. A few minutes later the party—the prisoners carefully guarded in the center, drew up in front of the mouldering door, and Black Ramon gave three raps with a rusty knocker.

"Who's there?" inquired a voice from within, in Spanish.

"The Black Kings of The Pass," rejoined Ramon in a loud tone.

The door creaked open and a squat figure stood revealed. But the door opener was not a Mexican, but a white man, and no very favorable specimen of his race, either.

"Jim Cummings!" gasped Coyote Pete, as his eyes fell on the other. "Well, the dern renegade!"

There was no time to ask questions just then. With a few rough words the prisoners were ordered to dismount, and were ushered under close guard into what seemed to have been the main body of the mission church. It had a high-vaulted ceiling, and a few windows high up from the floor and closely barred. Otherwise, it was bare, except for some straw thrown about as if for beds.

"You will stay here to-night," said Ramon, gruffly addressing the prisoners, "and in the morning we will talk."

Without another word he turned away, and the Border Boys and their companions heard the door close with a bang. Then came a metallic clang, which told that a heavy bar had been put in place outside.

"Bottled!" said Pete laconically, and with a calm that amazed Ralph.

"And corked!" added Walt.

Jack Merrill and Walt Phelps followed Pete's lead in taking the situation calmly. As a matter of fact, it was the only thing to do, but small blame can attach to Ralph for sinking down despondently on some of the straw as he heard the bar clang as if proclaiming their doom. As for the professor, he was strolling about, poking the walls with an inquiring finger and gazing in rapt admiration at the blackened beams of the roof above them.

"Well, there's one thing to be glad over," said Jack suddenly, "they haven't tied us."

"No need to," rejoined Pete. "We couldn't get out of here in a week, and—— Hark!"

They all listened intently. Outside they could hear the steady tramp-tramp of a man pacing up and down.

"A sentry!" exclaimed Walt Phelps.

"That's what. We're too valuable to Black Ramon for him to have us get away."

There seemed to be some hidden meaning underlying the cow-puncher's words, and the boys looked at him inquiringly.

"What I mean is," said the cow-puncher, "that this varmint sees a chance to make some money out of us. He knows your father would give a pile to get you back safe and sound, and I'll bet a busted sweat-leather he's going to hold you for ransom."

"But you, Pete?"

"Wall, I reckon he'll make chile-con-carne out of me," rejoined the cow-puncher with a grin. "I'm too tough for anything else."

A careful examination of the place, made as well as they could in the moon-checkered darkness, showed that Pete's diagnosis of their prison as "a bottle" was a correct one. The walls were solid, and appeared, just judging by the depth of the window embrasures, to be several feet thick. The windows themselves were far too high up to reach, even had they not been barred. The floor, after a careful tapping, yielded no sign of being hollow in any place.

"I was hoping we might find a hollow place somewhere," said Pete, in explaining this last maneuver. "You know these old padres lived a scary kind of life, and every once in a while their Indian converts would up and backslide and attack the church mission. So as they could do a quick getaway when such contingencies came loping along, they used to make tunnels, but I guess if these fellers that built this place tunneled they did it some other part."

"What you say is correct," chimed in the professor, more as if he was in the lecture room than a prisoner across the border, in the hands of ferocious cattle-rustlers; "the padre sometimes dug these tunnels so that they covered considerable distances. Burrows of this character, a mile or even more in length have been found in California."

"Wa'al, I wish we had the tools handy and we'd bore one ourselves," said Pete; "but as we ain't, the best thing we can do is to make ourselves as comfortable as possible and go to sleep. Things won't get no better for fretting over them, and we're in a fix now where things is bound to get a lot worse before they get better."

The cow-puncher, suiting the action to the word, lay down, and in a few moments his snores proclaimed that he slept. One after the other, the rest dozed off, till only Ralph remained awake. Jack Merrill had done his best to cheer the Eastern lad up before he sought refuge in slumber, but Ralph's position weighed on his mind too keenly to permit him to sleep. While the others lay stretched out in slumber he arose and began pacing the old church. He was not a superstitious lad, but the silence of the empty vaulted place, their position, and the uncertainty of their fate, all combined to fill him with a nervous dread.

Suddenly he stopped short in his pacing to and fro. Every nerve in his body tingled and his scalp tightened with alarm at a sudden sound he had heard.

Proceeding, it seemed, from the very masonry of the edifice itself, there had come a sound, which heard as it was, in those gloomy surroundings, was as terrifying as could be imagined.

"Who is there?" shouted the boy in frightened tones.

But the sound which he had heard ceased instantly. Nor, though he listened almost till dawn crept into the sky, and sleep overcame him, was it repeated.