So Moon-Watcher and his companions chewed berries and fruit and leaves and fought off the pangs of hunger – while all around them, competing for the same fodder, was a potential source of more food than they could ever hope to eat. Yet the thousands of tons of succulent meat roaming over the savanna and through the bush was not only beyond their reach; it was beyond their imagination. In the midst of plenty, they were slowly starving to death.

The tribe returned to its cave without incident, in the last light of the day. The injured female who had remained behind cooed with pleasure as Moon-Watcher gave her the berry-covered branch he had brought back, and began to attack it ravenously. There was little enough nourishment here, but it would help her to survive until the wound the leopard had given her had healed, and she could forage for herself again.

Over the valley, a full moon was rising, and a chill wind was blowing down from the distant mountains. It would be very cold tonight – but cold, like hunger, was not a matter for any real concern; it was merely part of the background of life.

Moon-Watcher barely stirred when the shrieks and screams echoed up the slope from one of the lower caves, and he did not need to hear the occasional growl of the leopard to know exactly what was happening.

Down there in the darkness old White Hair and his family were fighting and dying, and the thought that he might help in some way never crossed Moon-Watcher's mind. The harsh logic of survival ruled out such fancies, and not a voice was raised in protest from the listening hillside. Every cave was silent, lest it also attract disaster.

The tumult died away, and presently Moon-Watcher could hear the sound of a body being dragged over rocks. That lasted only a few seconds; then the leopard got a good hold on its kill. It made no further noise as it padded silently away, carrying its victim effortlessly in its jaws.

For a day or two, there would be no further danger here, but there might be other enemies abroad, taking advantage of this cold Little Sun that shone only by night. If there was sufficient warning, the smaller predators could sometimes be scared away by shouts and screams. Moon-Watcher crawled out of the cave, clambered onto a large boulder beside the entrance, and squatted there to survey the valley.

Of all the creatures who had yet walked on Earth, the man-apes were the first to look steadfastly at the Moon. And though he could not remember it, when he was very young Moon-Watcher would sometimes reach out and try to touch that ghostly face rising above the hills.

He had never succeeded, and now he was old enough to understand why. For first, of course, he must find a high enough tree to climb.

Sometimes he watched the valley, and sometimes he watched the Moon, but always he listened. Once or twice he dozed off, but he slept with a hair-trigger alertness, and the slightest sound would have disturbed him. At the great age of twenty-five, he was still in full possession of all his faculties; if his luck continued, and he avoided accidents, disease, predators, and starvation, he might survive for as much as another ten years.

The night wore on, cold and clear, without further alarms, and the Moon rose slowly amid equatorial constellations that no human eye would ever see. In the caves, between spells of fitful dozing and fearful waiting, were being born the nightmares of generations yet to be.

And twice there passed slowly across the sky, rising up to the zenith and descending into the east, a dazzling point of light more brilliant than any star.

Late that night, Moon-Watcher suddenly awoke. Tired out by the day's exertions and disasters, he had been sleeping more soundly than usual, yet he was instantly alert at the first faint scrabbling down in the valley.

He sat up in the fetid darkness of the cave, straining his senses out into the night, and fear crept slowly into his soul. Never in his life – already twice as long as most members of his species could expect – had he heard a sound like this. The great cats approached in silence, and the only thing that betrayed them was a rare slide of earth, or the occasional cracking of a twig. Yet this was a continuous crunching noise, that grew steadily louder. It seemed that some enormous beast was moving through the night, making no attempt at concealment, and ignoring all obstacles. Once Moon-Watcher heard the unmistakable sound of a bush, being uprooted; the elephants and dinotheria did this often enough, but otherwise they moved as silently as the cats.

And then there came a sound which Moon-Watcher could not possibly have identified, for it had never been heard before in the history of the world. It was the clank of metal upon stone.

Moon-Watcher came face to face with the New Rock when he led the tribe down to the river in the first light of morning. He had almost forgotten the terrors of the night, because nothing had happened after that initial noise, so he did not even associate this strange thing with danger or with fear. There was, after all, nothing in the least alarming about it.

It was a rectangular slab, three times his height but narrow enough to span with his arms, and it was made of some completely transparent material; indeed, it was not easy to see except when the rising sun glinted on its edges. As Moon-Watcher had never encountered ice, or even crystal-clear water, there were no natural objects to which he could compare this apparition. It was certainly rather attractive, and though he was wisely cautious of most new things, he did not hesitate for long before sidling up to it. As nothing happened, he put out his hand, and felt a cold, hard surface.

After several minutes of intense thought, he arrived at a brilliant explanation. It was a rock, of course, and it must have grown during the night. There were many plants that did this – white, pulpy things shaped like pebbles, that seemed to shoot up during the hours of darkness. It was true that they were small and round, whereas this was large and sharp-edged; but greater and later philosophers than Moon-Watcher would be prepared to overlook equally striking exceptions to their theories.

This really superb piece of abstract thinking led Moon-Watcher, after only three or four minutes, to a deduction which he immediately put to the test. The white round pebble-plants were very tasty (though there were a few that produced violent illness); perhaps this tall one...?

A few licks and attempted nibbles quickly disillusioned him. There was no nourishment here; so like a sensible man-ape, he continued on his way to the river and forgot all about the crystalline monolith, during the daily routine of shrieking at the Others.

The foraging today was very bad, and the tribe had to travel several miles from the caves to find any food at all. During the merciless heat of noon one of the frailer females collapsed, far from any possible shelter. Her companions gathered round her, twittering and meeping sympathetically, but there was nothing that anyone could do. If they had been less exhausted they might have carried her with them, but there was no surplus energy for such acts of kindness. She had to be left behind, to recover or not with her own resources. They passed the spot on the homeward trek that evening; there was not a bone to be seen.

In the last light of day, looking round anxiously for early hunters, they drank hastily at the stream and started the climb up to their caves. They were still a hundred yards from the New Rock when the sound began.

It was barely audible, yet it stopped them dead, so that they stood paralyzed on the trail with their jaws hanging slackly. A simple, maddeningly repetitious vibration, it pulsed out from the crystal; and hypnotized all who came within its spell. For the first time – and the last, for three million years – the sound of drumming was heard in Africa.