Up to that moment the cibolero had conceived no fixed plan of action.

How could he, where so much depended on chance?

Only one idea was before his mind that could be called definite--that was _to get Vizcarra alone_. If but for a single minute, it would suffice.

Entreaty, he felt, would be idle, and might waste time and end in his own defeat and death. A minute would be enough for vengeance; and with the thoughts of his sister's ruin fresh on his mind, he was burning for this. To anything after he scarce gave a thought. For escape, he trusted to chance and his own superior energy.

Up to that moment, then, he had conceived no fixed plan of action. It had just occurred to him that the Comandante himself might lead the party going out. If so he would take no immediate step. While acting as guide, his opportunity would be excellent--not only for destroying his enemy, but for his own escape. Once on the wide plains, he would have no fear of ten times the number of lancers. His true steed would carry him far beyond their reach.

The troop was going. The bugle told him so. Would Vizcarra go with it?

That was the question that now engrossed his thoughts, as he sat immobile on his horse, regarding with anxious look the line of the parapet above.

Once more the hated face appeared over the wall--this time to announce what the Comandante believed would be glad news to his wretched petitioner. With all the pompous importance of one who grants a great favour he announced it.

A gleam of joy shot over the features of the cibolero--not at the announcement, though Vizcarra thought so; but at his observation of the fact that the latter seemed to be now _alone upon the azotea_.

Roblado's face was not above the wall.

"It is exceedingly gracious of your excellency to grant this favour to an humble individual like myself. I know not how to thank you."

"No thanks--no thanks: an officer of his Catholic Majesty wants no thanks for doing his duty."

As the Comandante said this, he waved his hand with proud dignity, and seemed about to retire backward. Carlos interrupted his intention by putting a question: "Am I to have the honour of acting as guide to your excellency?"

"No; I do not go myself on this expedition; but my best officer, Captain Roblado, will lead it. He is now getting ready. You may wait for him."

As Vizcarra said this, he turned abruptly away from the wall, and continued his promenade along the azotea. No doubt he felt ill at ease in a _tete-a-tete_ with the cibolero, and was glad to end it. Why he had condescended to give all this information need not be inquired into; but it was just what the cibolero desired to know.

The latter saw that the time was come--not a moment was to be lost, and, quick as thought, he resolved himself for action.

Up to this moment he had remained in his saddle. His rifle--its butt resting in the stirrup, its barrel extending up to his shoulder--had been seen by no one. The "_armas de aqua_" covering his legs, and the serape his shoulders, had completely concealed it. In addition to this, his sharp hunting-knife, strapped along his left thigh, escaped observation under the hanging corner of the serape. These were his only weapons.

During the short conversation between the Comandante and Roblado he had not been idle, though apparently so. He had made a full reconnaissance of the walls. He saw that out of the saguan, or gateway, an escalera of stone steps led up to the azotea. This communication was intended for the soldiers, when any duty required them to mount to the roof; but Carlos knew that there was another escalera, by which the officers ascended: and although he had never been inside the Presidio, he rightly conjectured that this was at the adjacent end of the building. He had observed, too, that but one sentry was posted at the gate, and that the stone banquette, inside the saguan, used as a lounging-place by the guard, was at the moment unoccupied. The guard were either inside the house, or had strayed away to their quarters. In fact, the discipline of the place was of the loosest kind. Vizcarra, though a dandy himself, was no martinet with his men. His time was too much taken up with his own pleasures to allow him to care for aught else.

All these points had passed under the keen observation of the cibolero before Vizcarra returned to announce his intention of sending the troop.

He had scarce parted out of sight the second time ere the former had taken his measures.

Silently dismounting from his horse, Carlos left the animal standing where he had halted him. He did not fasten him to either rail or post, but simply hooked the bridle-rein over the "horn" of the saddle. He know that his well-trained steed would await him there.

His rifle he still carried under his serape, though the butt was now visible below the edge, pressed closely against the calf of his leg. In this way he walked forward to the gate.

One doubt troubled him--would the sentry permit him to pass in? If not, the sentry must die!

This resolve was quickly made; and the cibolero under his serape kept his grasp on the handle of his hunting-knife as he approached the gate.

The attempt was made to pass through. Fortunately for Carlos, and for the sentry as well, it was successful. The latter--a slouching, careless fellow--had heard the late conversation, and had no suspicion of the other's design. He made some feeble opposition, notwithstanding; but Carlos hastily replied that he had something to say to the Comandante, who had beckoned him up to the azotea. This but half satisfied the fellow, who, however, reluctantly allowed him to pass.

Once inside, Carlos sprang to the steps, and glided up with the stealthy silent tread of a cat. So little noise had his moccasins made upon the stones, that, when he arrived upon the roof, its occupant--although standing but six feet from the head of the escalera--was not aware of his presence!

There was he--Vizcarra himself--the despot--the despoiler--the violator of a sister's innocence and honour--there was he within six feet of the avenging brother--six feet from the muzzle of his ready rifle, and still ignorant of the terrible situation! His face was turned in an opposite direction--he saw not his peril.

The glance of the cibolero rested upon him but an instant, and then swept the walls to ascertain if any one was above. He knew there were two sentries on the towers. They were not visible--they were on the outer walls and could not be seen from Carlos's position. No one else was above. His enemy alone was there, and his glance again rested upon him.

Carlos could have sent the bullet into his back, and such a thought crossed his mind, but was gone in an instant. He had come to take the man's life, but not in that manner. Even prudence suggested a better plan. His knife would be more silent, and afford him a safer chance of escape when the deed was done! With this idea, he brought the butt of his rifle gently to the ground, and rested its barrel against the parapet. The iron coming in contact with the stone wall gave a tiny clink. Slight as it was, it reached the ear of the Comandante, who wheeled suddenly round, and started at the sight of the intruder.

At first he exhibited anger, but the countenance of the cibolero, that had undergone a complete metamorphosis during the short interval, soon changed his anger into alarm.

"How dare you intrude, sir?--how dare--"

"Not so loud, colonel!--not so loud--you will be heard!"

The low husky voice, and the firm tone of command, in which they were uttered, terrified the cowardly wretch to whom these words were addressed. He saw that the man who stood before him bore in his face and attitude the expression of desperate and irresistible resolve, that plainly said, "Disobey, and you are a dead man!" This expression was heightened by the gleaming blade of a long knife, whose haft was firmly grasped by the hand of the cibolero.

At sight of those demonstrations, Vizcarra turned white with terror. He now comprehended what was meant. The asking for the troop had been but a subterfuge to get near his own person! The cibolero had tracked him; his guilt was known, and the brother was now come to demand redress or have vengeance! The horrors of his night-dream returned, now mingling with the horrors of the fearful reality before him.

He scarce knew what to say--he could scarce speak. He looked wildly around in hopes of seeing some help. Not a face or form was in sight-- nothing but the grey walls, and before him the frowning face of his terrible antagonist. He would have called for help; but that face--that angry attitude--told him that the shout would be his last. He gasped out at length--

"What want you?"

"_I want my sister_!"

"Your sister?"

"My sister!"

"Carlos--I know not--she is not here--I--"

"Liar! she is within these walls. See! yonder the dog howls by the door. Why is that?"

Carlos pointed to a door in the lower part of the building, where the dog Cibolo was at that moment seen, whining and making other demonstrations, as if he wanted to get inside! A soldier was endeavouring to drive him off.

Vizcarra looked mechanically as directed. He saw the dog. He saw the soldier too; but dared not make a signal to him. The keen blade was gleaming before his eyes. The question of the cibolero was repeated.

"Why is that?"

"I--I--know not--"

"Liar again! She has gone in by that door. Where is she now? Quick, tell me!"

"I declare, I know not. Believe me--"

"False villain! she is here. I have tracked you through all your paths--your tricks have not served you. Deny her once more, and this to your heart. She is here!--Where--where--I say?"

"Oh! do not murder me. I shall tell all. She--she--is--here. I swear I have not wronged her; I swear I have not--"

"Here, ruffian--stand at this point--close to the wall here.--Quick!"

The cibolero had indicated a spot from which part of the patio, or courtyard, was visible. His command was instantly obeyed, for the craven Comandante saw that certain death was the alternative.

"Now give orders that she be brought forth! You know to whom she is intrusted. Be cool and calm, do you hear? Any sign to your minions, either word or gesture, and this knife will pass through your ribs!

Now!"