From the vantage point of the wall he had seen lights a short distance above the level of the main part of the city and what seemed to be the shadowy outlines of a large building. That, he conjectured, must be the castle of God, of which Naomi Madison had spoken.

If he were right, that would be his goal; for there the other girl was supposed to be imprisoned. He moved along the face of the cliff in a narrow, winding alley that followed generally the contour of the base of the mountain, though sometimes it wound around buildings that had been built against the cliff.

He hoped that he would meet none of the denizens of the city, for the passage was so narrow that he could not avoid detection; and it was so winding that an enemy might be upon him before he could find concealment in a shadowy doorway or upon a rooftop, which latter he had decided would make the safest hiding place and easy of access, since many of the buildings were low.

He heard voices and saw the dim glow of lights in another part of the city, and presently there rose above the strange city the booming of drums.

Shortly thereafter Tarzan came to a flight of steps cut from the living rock of the cliff. They led upward, disappearing in the gloom above; but they pointed in the general direction of the building he wished to reach. Pausing only long enough to reconnoiter with his ears, the ape-man started the ascent.

He had climbed but a short distance when he turned to see the city spread out below him. Not far from the foot of the cliff rose the towers and battlements of what appeared to be a medieval castle. From within its outer walls came the light that he had seen dimly from another part of the city; from here too came the sound of drumming. It was reminiscent of another day, another scene. In retrospection it all came vividly before him now.

He saw the shaggy figures of the great apes of the tribe of Kerchak. He saw an earthen drum. About it the apes were forming a great circle. The females and the young squatted in a thin line at its periphery, while just in front of them ranged the adult males. Before the drum sat three old females, each armed with a knotted branch fifteen or eighteen inches in length.

Slowly and softly they began tapping upon the resounding surface of the drum as the first, faint rays of the ascending moon silvered the encircling tree-tops. Then, as the light in the amphitheater increased, the females augmented the frequency and force of their blows until presently a wild, rhythmic din pervaded the great jungle for miles in every direction.

As the din of the drum rose to almost deafening volume Kerchak sprang into the open space between the squatting males and the drummers. Standing erect he threw his head far back and looking full into the eye of the rising moon he beat upon his breast with his great hairy paws and emitted a fearful, roaring shriek.

Then, crouching, Kerchak slunk noiselessly around the open circle, veering away from a dead body that lay before the altar-drum; but, as he passed, keeping his fierce, wicked eyes upon the corpse.