They had no idea of where they were going. They had only one goal in view—to put as big a distance as they could between themselves and the purple people whom they knew would already be following them. Suddenly the road ended. They had turned a sharp corner and the way had opened out into a small cave, which was bounded on one side by a narrow strip of bubbling, foaming water, that disappeared at either end in a dark tunnel. “What shall we do?” asked Desmond. “Shall we go back?”

“We can’t,” said Alan decisively. “The road that brought us here was at least five miles long, without a turn in it. By the time we retraced our steps, the purple devils would have caught up to us. No, old boy, I think this is a tight fix we are in, and at the moment I can’t quite see how we are to get out of it.”

They walked round the little cave examining it carefully. It had only the one exit—the path up which they had come. The tunnels at either end through which flowed the waters were too low to admit the passage of a body, and the walls on the other side of the little river rose sheer from the water itself. “It looks pretty hopeless,” said Alan at last, “but at all costs we must not go back.”

“How red the walls are,” said Desmond suddenly. Alan started, for in his mind he could hear a voice saying, “Look for the stones that are red.” It had been Har-Barim’s advice to them, and he had said—“make for the waters that are turbulent and wild—where in the space of a foot—” A foot! why the water couldn’t be wider than that here. He looked round hurriedly—was it his fancy or were the stones on the opposite side even redder than those about him?

To Alan’s strained nerves it seemed as if just opposite him a stone had been worn away by the constant passage of feet. Slowly a thought came into his mind—if that was a footprint then surely it must lead somewhere. His eyes travelled up the rock eagerly—again his quickened senses discovered another foothold a little higher up, and still another and another. Four in all, at perhaps a stretch of a little over two feet. Upward his glance wandered, and in the rugged rock he saw a flat piece of red stone that looked as if it had been inserted there at some time or other, for some specific purpose. He stretched across the raging torrent and with a mighty effort clung to the jagged rock. “Don’t touch me, Dez,” he commanded, “I think I can manage best alone.”

With an almost superhuman effort he placed his foot in the first little cleft, and gradually worked up to the little red stone that had so aroused his curiosity. Desmond watched him in breathless horror. Although the water was so narrow, Alan would stand little chance of saving himself if he fell in, for it was dashing wildly against the sides and sending its spray even higher than where Alan was clinging. He touched the stone—it moved ever so slightly. “God! A secret way!” he cried, and worked feverishly to open it. But although it trembled and shook, it would not disclose its secret.

Then, away in the distance, came the sound of fierce shouting and the beating of drums.

“The people know,” cried Desmond. “They are coming up the long passage.” Already they could hear the name of Kaweeka used as a battle cry, and they realized that they could expect little mercy if they were caught by the purple savages.

With beads of perspiration on his brow, Alan worked. His fingers were torn and bleeding from his exertions. Still nearer came the cries of the infuriated people, and Alan had not yet succeeded in moving the stone, which he was convinced hid a secret way of escape. Desmond ran down the passage a little way—in a second he was back. “I can see them,” he cried. “There are hundreds of them! Oh, what shall we do?”

“Ah!” Alan gave a cry of relief, for suddenly the stone had rolled back, revealing a small cavity beyond, just big enough for the passage of a man’s body.