Their progress was slow but silent, neither venturing to exchange speech, but with ears anxiously strained to catch the least sound.  Stella was conscious of the loud beating of her heart, the slight rasping of Cavendish’s feet on the rock floor.  The slightest noise seemed magnified.  The grade rose sharply, until it became almost a climb, yet the floor had evidently been levelled, and there were no obstructions to add to the difficulty of advance.  Then the passage swerved rather sharply to the right, and Cavendish, leading, halted to peer about the corner.  An instant they both remained motionless, and then, seeing and hearing nothing, she could restrain her impatience no longer.

“What is it?” she questioned.  “Is there something wrong?”

He reached back and drew her closer, without answering, until her eyes also were able to look around the sharp edge of rock.  Far away, it seemed a long distance up that narrow tunnel, a lantern glowed dully, the light so dim and flickering as to scarcely reveal even its immediate surroundings; yet from that distance, her eyes accustomed to the dense gloom, she could distinguish enough to quicken her breathing and cause her to clutch the sleeve of her companion.

The lantern occupied a niche in the side wall at the bottom of a flight of rude steps.  Not more than a half-dozen of these were revealed, but at their foot, where the passage had been widened somewhat, extended a stone bench, on which lounged two men.  One was lying back, his head pillowed on a rolled coat, yet was evidently awake; for the other, seated below him, with knees drawn up for comfort, kept up conversation in a low voice, the words being inaudible at that distance.  Even in that dim light the two were clearly Mexican.

“What shall we do?” she asked, her lips at Cavendish’s ear.  “We cannot pass them—­they are on guard.”

“I was wondering how close I could creep in before they saw me,” he answered, using the same caution.  “If I was only sure they were alone, and could once get the drop, we might make it.”

“You fear there may be others posted at the top?”

“There is quite likely to be; the fellows are evidently taking no chances of surprise.  What do you think best?”

“Even if you succeeded in overawing these two, we would have no way of securing them.  An alarm would be given before we could get beyond reach.  Our only hope of escape lies in getting out of here unseen.”

“Yes, and before Cateras is discovered.”

“He gave no orders to the guard to return?”

“No; but he will be missed after a while and sought for.  We cannot count on any long delay, and when it is found that he has been knocked out, and we have disappeared, every inch of this cave will be searched.  There is no place to hide, and only the two ways by which to get out.”

“Then, let’s go back and try the other,” she urged.  “That opens directly into the valley and is probably not guarded.  What is happening now?”