There was no sign of life. In the distance loomed the tunnel mouth by which they had entered Alu. Tony slid along the side of the building and peered gingerly around the corner. He could see the arched ramp along which the “gods” had passed, but it was vacant now. What was the logical course to pursue? The lost city stretched about for miles, an apparently tenantless ruin. Yet it was peopled, Tony knew, by Thotmes the high priest and his servitors—perhaps by Copts, though probably not, since the latter were confined to their own city above. At the thought Tony involuntarily glanced up. Beyond the cavern roof was the Midnight Sea, above that the Coptic city, and still further above, Sub-Sahara itself. The weight of innumerable tons of Earth pressing down on him was almost suffocating. However— Tony shook off the feeling and set out at random, after taking careful bearings. He had a compass, but it was useless in this environment, as he found after brief experimentation. But he could gauge direction fairly well from the great pyramid, which was visible from almost any point in the city of Alu. He kept in the shadows, which were concealingly dark where the flickering red light did not shine. What caused that volcanic glow Tony did not know, though he hazarded a few guesses. He went toward the pyramid. It was a metropolis of the dead. Eons ago it had been inhabited, by the survivors of sunken Atlantis, but now only the dust of ages filled it. Silence, and everywhere the symbol of Isis, Moon-goddess, carved upon the stones. Silence ... The pyramid drew nearer, and Tony was amazed anew at its hugeness. It towered up and up to the very ceiling of the cavern, seeming to support it like a pillar. Perhaps it did—he could not tell. But as he came closer he saw that the pyramid was hollow, for there were lighted embrasures here and there in the sloping expanse of its sides. And still there was no sound, no movement, no trace of life. Tony grew more cautious, though there seemed no need. An arched opening loomed in the side of the pyramid near him, and he slunk toward it watchfully. No guards were posted. He hesitated near the threshold. Should he take the risk of entering what might be a stronghold of his enemies? To search the deserted city was seemingly a vain task, and, shrugging, Tony walked boldly toward the opening. But his gun was in his hand, and a coal-cartridge in its cup, ready for instant use. * * * * * A passageway sloped upward within the pyramid. It was lighted dimly by gleaming bars like neon-tubes that ran the length of the ceiling. In the vague glow Tony went stealthily on.