During the next few seconds Bob's brain was in a whirl. He had half a mind to shoot the fellow outright and take no chances. But a moment later he thought better of it. He did not want to be guilty of murdering even this cruel Arab. If he had been as good a shot with a pistol as he was with a rifle, he would have shot the knife from the fellow's hand. But as it was, he knew this could not be done. Suddenly the Arab lowered the knife and, scowling cruelly, he rushed at the youth furiously. Realizing that he must act quickly, Bob aimed at the man's leg and fired. But his hand was unsteady from the terrific strain, and the bullet missed and lodged itself in the wall. With a hoarse bellow the Arab came forward with terrific force, muttering angrily. He had the knife in readiness now, and was about to plunge it into the youth's body when something unexpected happened. Seeing a good chance, Bob pushed his foot forward with all his strength, bringing the man down with a thud that resounded through the little room. The Arab was taken completely unawares, and the knife went sliding across the floor. The next instant he was on his feet, and, showing his black teeth wickedly, he darted toward his young enemy, his large hands ready to grip anything they might rest on. Now was the time to act, Bob thought. Leaping forward, he sent his fist crashing into the Arab's nose with all the strength in his powerful young body. The man reeled, backed up, and then fell against the wall. Another victim of the youth's boxing ability had gone to his fate. Perspiration was dripping from the boy's brow. His leg ached from the twist he gave it in bringing the Arab to the floor. Every muscle in his body seemed fatigued. For a brief moment a sensation of nothingness crept over him, and he felt slightly numb. With a start he regained his composure and, with one glance at the still limp Arab, he dashed through the door, the shining automatic still in his possession. One thought stood out in his mind above all others. He must find Fekmah. No one was in the alcove, but another door led out into a sort of hallway, and casting aside all thoughts of personal danger, Bob passed through it. The next instant he found himself in a narrow passageway, with no windows or other means to admit light. The semidarkness was tantalizing, overcoming, but the boy went bravely on. Occasionally he stopped to listen. But no sound reached his ears. Could it be possible that Fekmah had been.... The thought was not a pleasant one, and Bob dismissed it from mind. Here was a door. Perhaps this would reveal something. As quietly as possible he turned the latch and peeped in the room. In the darkness he could make out no one at first. Then his eyes almost burst from his head as he saw, lying on the floor in the corner, tightly bound and gagged--Fekmah! For a moment Bob stood spellbound. Then he rushed over to the unfortunate man.