As he fumbled with the straps that were to convert him into a beast of burden, Alvin looked doubtfully at the great mass of rock before them.

             "It's a long way around, isn't it?" he queried.

             "We aren't going around," replied Theon. "I want to get to the top before nightfall."

             Alvin said nothing. He had been rather afraid of this.

             "From here," said Theon, raising his voice to make it heard above the thunder of the waterfall, "you can see the whole of Lys."

             Alvin could well believe him. To the north lay mile upon mile of forest, broken here and there by clearings and fields and the wandering threads of a hundred rivers. Hidden somewhere in that vast panorama was the village of Airlee. Alvin fancied that he could catch a glimpse of the great lake, but decided that his eyes had tricked him. Still farther north, trees and clearings alike were lost in a mottled carpet of green, rucked here and there by lines of hills. And beyond that, at the very edge of vision, the mountains that hemmed Lys from the desert lay like a bank of distant clouds.

             East and west the view was little different, but to the south the mountains seemed only a few miles away. Alvin could see them very clearly, and he realized that they were far higher than the little peak on which he was standing.

             But more wonderful even than these was the waterfall. From the sheer face of the mountain a mighty ribbon of water leaped far out over the valley, curving down through space toward the rocks a thousand feet below. There it was lost in a shimmering mist of spray, while up from the depths rose a ceaseless, drumming thunder that reverberated in hollow echoes from the mountain walls. And quivering in the air above the base of the fall was the last rainbow left on Earth.

             For long minutes the two boys lay on the edge of the cliff, gazing at this last Niagara and the unknown land beyond. It was very different from the country they had left, for in some indefinable way it seemed deserted and empty. Man had not lived here for many, many years.

             Theon answered his friend's unspoken question.

             "Once the whole of Lys was inhabited," he said, "but that was a very long time ago. Only the animals live here now."

             Indeed, there was nowhere any sign of human life—none of the clearings or well-disciplined rivers that spoke of Man's presence. Only in one spot was there any indication that he had ever lived here, for many miles away a solitary white ruin jutted above the forest roof like a broken fang. Elsewhere, the jungle had returned to its own.

7.

             It was night when Alvin awoke, the utter night of mountain country, terrifying in its intensity. Something had disturbed him, some whisper of sound that had crept into his mind above the dull thunder of the falls. He sat up in the darkness, straining his eyes across the hidden land, while with indrawn breath he listened to the drumming roar of the falls and the faint but unending rustle of life in the trees around him.

             Nothing was visible. The starlight was too dim to reveal the miles of country that lay hundreds of feet below: only a jagged line of darker night eclipsing the stars told of the mountains on the southern horizon. In the darkness beside him Alvin heard his friend roll over and sit up.

             "What is it?" came a whispered voice.

             "I thought I heard a noise."

             "What sort of noise?"

             "I don't know. Perhaps I was only dreaming."

             There was silence while two pairs of eyes peered out into the mystery of night. Then, suddenly, Theon caught his friend's arm.

             "Look!" he whispered.

             Far to the south glowed a solitary point of light, too low in the heavens to be a star. It was a brilliant white, tinged with violet, and as the boys watched it began to climb the spectrum of intensity, until the eye could no longer bear to look upon it. Then it exploded—and it seemed as if lightning had struck below the rim of the world. For an instant the mountains, and the great land they guarded, were etched with fire against the darkness of the night. Ages later came the echo of a mighty explosion, and in the forest below a sudden wind stirred among the trees. It died away swiftly, and one by one the routed stars crept back into the sky.

             For the first time in his life, Alvin knew that fear of the unknown that had been the curse of ancient Man. It was a feeling so strange that for a while he could not even give it a name. In the moment of recognition it vanished and he became himself again.

             "What is it?" he whispered.

             There was a pause so long that he repeated the question.

             "I'm trying to remember," said Theon, and was silent for a while. A little later he spoke again.

             "That must be Shalmirane," he said simply.

             "Shalmirane! Does it still exist?"

             "I'd almost forgotten," replied Theon, "but it's coming back now. Mother once told me that the fortress lies in those mountains. Of course, it's been in ruins for ages, but someone is still supposed to live there."

             Shalmirane! To these children of two races, so widely differing in culture and history, this was indeed a name of magic. In all the long story of Earth there had been no greater epic than the defense of Shalmirane against an invader who had conquered all the Universe.

             Presently Theon's voice came again out of the darkness.

             "The people of the south could tell us more. We will ask them on our way back."

             Alvin scarcely heard him: he was deep in his own thoughts, remembering stories that Rorden had told him long ago. The Battle of Shalmirane lay at the dawn of recorded history: it marked the end of the legendary ages of Man's conquests, and the beginning of his long decline. In Shalmirane, if anywhere on Earth, lay the answers to the problems that had tormented him for so many years. But the southern mountains were very far away.

             Theon must have shared something of his mother's powers, for he said quietly:

             "If we started at dawn, we could reach the fortress by nightfall. I've never been there, but I think I could find the way."

             Alvin thought it over. He was tired, his feet were sore, and the muscles of his thighs were aching with the unaccustomed effort. It was very tempting to leave it until another time. Yet there might be no other time, and there was even the possibility that the actinic explosion had been a signal for help.

             Beneath the dim light of the failing stars, Alvin wrestled with his thoughts and presently made his decision. Nothing had changed: the mountains resumed their watch over the sleeping land. But a turning-point in history had come and gone, and the human race was moving toward a strange new future.

             The sun had just lifted above the eastern wall of Lys when they reached the outskirts of the forest. Here, Nature had returned to her own. Even Theon seemed lost among the gigantic trees that blocked the sunlight and cast pools of shadow on the jungle floor. Fortunately the river from the fall flowed south in a line too straight to be altogether natural, and by keeping to its edge they could avoid the denser undergrowth. A good deal of Theon's time was spent in controlling Krif, who disappeared occasionally into the jungle or went skimming wildly across the water. Even Alvin, to whom everything was still so new, could feel that the forest had a fascination not possessed by the smaller, more cultivated woods of northern Lys. Few trees were alike: most of them were in various stages of devolution and some had reverted through the ages almost to their original, natural forms. Many were obviously not of Earth at all—perhaps not even of the Solar System. Watching like sentinels over the lesser trees were giant sequoias, three and four hundred feet high. They had once been called the oldest things on Earth: they were still a little older than Man.