Asmak made a semi-obeisance, symbolic of acquiescence. Then he turned toward the door, gesturing for Niall to follow.

As they descended the stairs to the hallway, Niall experienced misgivings. He had a suspicion that his simple inquiry had given rise to some misunderstanding, whose nature escaped him. Yet there was something about Asmak's manner that aroused intense curiosity. His perplexity increased when, instead of crossing the flagstones to the main door, Asmak turned to the right and descended a further flight of stairs. Niall found himself in total darkness, and had to place a hand on the wall to recover his bearings. A moment later, as the stairs made a right-angle turn, he tripped and stumbled; it was Grel who saved him from falling by hooking a foreleg around his waist. Asmak immediately recognized his difficulty, and extended assistance. The darkness seemed to vanish, to be replaced by a soft luminescence which enabled Niall to see the walls and the stairway. It took several moments for him to realize that he was still in complete darkness, and that the spider was simply conveying a kind of mental picture of their surroundings, exactly as on the "flight" over the mountains.

Niall had expected to be led into some kind of cellar or underground vault; instead, he found himself turning more right-angle bends and descending further flights of stairs. When they finally reached level ground, Niall calculated that they must be as far below the roadway as the roof of the tower was above it.

The corridor in which he found himself was about six feet wide and seven feet high; its ceiling was curved, and, like the walls, was made of irregular stones set in cement. Asmak's height meant that he had to walk with his belly lowered, to avoid striking his head on the ceiling; from this, Niall deduced that the tunnel had not been built by spiders, or for them.

A dozen yards ahead, the corridor was blocked by a massive door, whose timbers were held together by wrought-iron bands. As they approached, there were sounds of bolts being withdrawn; then the door swung open to reveal a brown wolf spider, who immediately prostrated himself at Asmak's feet. There was some kind of interchange -- spiders were always punctilious in greeting one another -- then the wolf spider withdrew into an alcove in the wall, leaving them room to pass. For a moment Niall felt sorry for him, standing guard for hour after hour in this cold darkness -- until he recalled that all the spiders in this city were bound together in a kind of mutual awareness, and that therefore no spider was ever completely alone. It was the human beings who deserved pity.

The air was damp, and had a smell of mildew; it was also extremely cold, although Niall experienced no discomfort -- his contact with the spider's mind ensured that his body remained pleasantly warm, as if he had been taking vigorous exercise on a winter's day.

It also ensured that, although the spider's body would normally have blocked his view along the tunnel, he was able to "see" for a considerable distance beyond it. He was impressed by the fact that Asmak must have been familiar with literally every inch of their surroundings, for his mind reflected them as literally as if he had been able to see them. There were places where the walls had fallen into a state of disrepair, and slabs of stone lay on the ground. In another place, the ceiling had started to collapse and had been supported by balks of timber, including a beam that lay across the floor holding the uprights in place. Asmak skirted such obstacles without the slightest hesitation. At one point, the corridor was crossed by a lower tunnel with a downhill slope, and the ground there was covered with a slimy liquid with an unpleasant smell of stagnation; Asmak's warning of the slippery surface caused him to tread cautiously, and enabled him to avoid a fall.

So far, Niall had shared the spider's mental states in the sense of being an onlooker. His awareness of what was being communicated by Asmak was more direct than listening to a human voice, yet essentially of the same nature. But now, as he allowed himself to relax, he found that his own consciousness was beginning to blend with Asmak's, so that it was difficult to tell where his own began and Asmak's ended. It was an extraordinary sensation. To begin with, Asmak's consciousness was so much "stronger" than his own that it made him acutely aware of the inadequacies of the human mind. He was reminded of the state he achieved when using the thought mirror, which amplified the will. But the thought mirror was tiring; it left him physically drained.

Spider consciousness had a tremendous, unflagging power which somehow renewed itself through its own sheer enthusiasm and interest in the world. Yet although Niall found this marvelously exhilarating, he was not entirely happy about it. There was something crude and practical about this spider consciousness; it failed to satisfy some deep hunger for subtlety and complexity. . .

He was aroused from these reflections by the realization that they were no longer walking along a man-made tunnel. It had widened, and the walls on either side of him were made of a white rocklike material that might have been chalk or limestone. The ground underfoot was irregular, although there were many places where it had obviously been leveled with tools. A hundred yards further on, the tunnel widened again, and they were in a wide gallery whose roof was supported by irregular pillars of the white rock. It was obvious to Niall that this had been carved by water in some remote geological era. Shallow pools of water still covered the irregular floor; they waded through one that was ankle-deep, and the water was icy. Drops of water fell from the ceiling, and the sound was unusually loud in the stillness.

They had been walking for almost half an hour, and had probably covered a distance of more than two miles. Niall found himself wondering which direction they had taken; his question was "overheard" by the spider, who immediately made him aware that they were walking due east. As far as Niall could calculate, that placed them somewhere beneath the "industrial estate" to the east of the main square.

Ten minutes later, he became aware of another sound, like a distant rumble. As it grew louder, he realized that it was the sound of rushing water. And in spite of his sense of heightened vitality, he found it hard to suppress a rising nervous tension. This was not due to any lack of trust in Asmak's guidance, but merely to an instinctive fear of unknown perils. It cost a genuine effort to assure himself that Asmak would not allow any harm to befall him.

Moments later, the rushing sound filled the air like a tempest, and they came to a halt on the bank of a wide river. The black water was flowing very fast, but so smoothly that only a few ripples on its surface betrayed its speed. Niall was relieved to see that it was spanned by a metal bridge with a railing on either side; as they walked across this, the water flowed only a few inches below their feet. In the center of the bridge -- which was made of welded metal plates -- the noise was deafening; Niall's impression was that the river plunged over a waterfall, perhaps another quarter of a mile downstream. Asmak, he noticed, was also nervous; like all death spiders, he had a natural dislike of water.

On the far side of the river, the nature of the terrain changed; the white rock was replaced by a dark, granitelike substance. They were no longer walking along a tunnel, but along some kind of cleft in the rock; Niall surmised that it had been caused by an earthquake or volcanic eruption, and again the thought made him irrationally nervous.

The ground sloped toward the left, and it was necessary to walk carefully to avoid slipping. This "road" twisted and turned between sheer rock faces. The sound of water was soon left behind them, and they were once again walking in a silence in which Niall's footsteps sounded eerily loud. (The spiders walked as softly as cats.) He could now recognize in Asmak a sense of anticipation that told him that they were drawing close to their goal. He could easily have learned the nature of this goal by seeking access to a deeper level of Asmak's consciousness; but he sensed that the spider would regard such uncontrolled curiosity with a certain disapproval.

The rock faces on either side now came closer together, and finally joined overhead to form a pointed arch. The rocky path underfoot had obviously been leveled, but the sheer hardness of the rock had frustrated all efforts to make it smooth, and Niall had to tread carefully to avoid twisting his ankle. Grel and Asmak had no such problem; the number of their legs made it virtually impossible for them to stumble. But as the tunnel became narrower and lower, both had to bend their legs, so that their bellies were close to the ground. A point came where the walls were scarcely a yard apart, and Niall had to bend his head to avoid striking it on the roof. Asmak had to walk very slowly to squeeze his considerable bulk between the walls. Then, just as Niall was beginning to feel claustrophobic, the tunnel widened suddenly and came to an end.

He found himself standing in a large cave, whose roof was perhaps fifty feet above them. As far as he could see, there was no other way out; the cave was virtually a cul-de-sac. But he was aware of its size only because he was "seeing" it through Asmak's mind; like the lair of the Death Lord, it was so full of cobwebs that even the most powerful light could not have pierced its depths. Cobwebs stretched like vast curtains from the walls to the floor; others, with strands like thick rope, stretched across the ceiling. But these were not the casually arranged cobwebs that formed a network above most of the streets of the spider city; Niall sensed immediately that they had been created by an artistic intelligence of a high order, and that their strange symmetry had some profound meaning for the spider mind. Unlike the dust-covered cobwebs in the headquarters of the Death Lord, these looked new and sticky; they even carried the faint, distinctive smell -- not unlike some vegetable gum -- of fresh cobwebs. This place, he realized, was a kind of spider cathedral, a place of worship, and the cobwebs were its woven tapestries, constantly renewed as an act of homage.

Slight sounds from overhead made him aware that spiders were lurking there.

Although the cave was in total darkness, Asmak's familiarity with its geography, and his telepathic awareness of other spiders, created an illusion of a kind of gray twilight in which everything was clearly visible. He was able to sense that the spiders were all young -- some even younger than Grel -- and that there were about a dozen of them. Their youth was obvious because they were transmitting involuntary signals of excitement at the interruption of their lonely vigil; an older spider would have learned to restrain these signals. It was also clear to Niall that they were intensely curious about his own presence.

Asmak stood there silently for several minutes, waiting for this buzz of excitement to die down. Spiders always took their time in greeting one another -- it was a point of honor as well as a natural instinct. During this time, Niall's mind was able to explore the recesses of the cave. Running up the far wall he could see a kind of ascending ramp, not unlike a flight of steps, which had obviously been carved out of the rock. This suggested that human beings sometimes made use of this cave -- for spiders, in spite of their weight, would have no difficulty scaling its uneven walls. He was also able to perceive a number of deep recesses in the walls, all at floor level, although these appeared to be empty. Since these were all of the same size, and at regular intervals, it was clear that they had been carved by human workmen.

Niall was puzzled. He had been expecting to meet some older spider who might be able to answer his questions about the great wall. In fact, it was obvious that none of the spiders present had passed beyond the age which in human beings would be regarded as puberty.

Asmak finally spoke. The message he transmitted was a formal one of greeting; after a decent interval, it was answered by the young spiders speaking in unison. This proceeding had the effect of finally blocking off the signals of curiosity that were still being transmitted by the younger spiders.

Asmak's greeting, and the answer of the young spiders, had been an instantaneous telepathic signal, whose human equivalent would have been a bow or a handshake. Now Asmak deliberately spoke in human language -- that is, in the type of signal that spiders used to communicate with human beings.

"The person I have brought with me is an honorary spider." Asmak said "person"

rather than "human being" because among spiders, "human being" was a term of contempt -- like "pig" among humans. "He is also the lord of our city." This statement caused a buzz of astonishment among the young spiders, and Niall inferred from it that they knew nothing of what had taken place in the past six months. This in turn implied that these young spiders had been living in this cold darkness since the days of slavery.

Were they being punished? Or perhaps trained for some kind of priesthood? The latter seemed perhaps the most likely.

Asmak resumed: "He is also the chosen one of the great goddess, and therefore our master."

For a few seconds there was total silence, unbroken by even a quiver of astonishment. Then Niall heard the rustling sound of soft, furry bodies descending on strands of web. A moment later he was surrounded by spiders who had lowered their stomachs to the ground in a gesture of homage. He stood there, feeling awkward and embarrassed, yet realizing that this was an essential part of spider ritual, and that he would be showing discourtesy if he allowed the slightest hint of his embarrassment to become apparent. As the moments lengthened, he realized that they were awaiting some gesture on his part. He therefore said aloud: "Greetings," accompanying it with a courteous gesture of acknowledgment. The ritual reply -- "Greetings, lord" -- came back like an echo; it was followed immediately by the rustling sound of spiders reabsorbing their strands of silk, and ascending once more into their webs. As this happened, Niall felt his body pierced by a pleasant glow, as warm and delicious as a spring breeze, and realized that the young spiders were transmitting a message of respect and affection. His sense of awkwardness vanished, and was replaced by an answering warmth and affection.

It was as if some barrier inside him had broken down, and he could accept for the first time that he was truly an "honorary spider."

Asmak spoke again. "Do any of you know the history of the great wall across the Valley of the Dead?"

Niall was astonished by the question. How could these young spiders know anything of the ancient history of their race? In fact, the silence that greeted the question seemed to indicate that they found it baffling. But after a long pause, a voice replied from above him in the darkness.

"I think it may have been built in the reign of Cheb the Mighty."

Asmak said: "Very well. Let us consult him. Are you his preserver?"

A voice from another part of the hall answered: "No, lord, I am."

"Good. Take us into his presence."

Niall was baffled; his sensitivity to the aura of living creatures made him certain that this place contained none apart from themselves.

There was a soft rustle as a young spider descended to the ground. As he made the ritual obeisance before him, Niall realized that he was little more than a child -- the equivalent of a human seven-year-old. He was so young that his poison fangs had not even begun to develop. He spoke to Niall haltingly, as one who was unused to human speech.

"Please, follow me, sire."

He led him toward one of the recesses that Niall had already observed. Asmak stood aside to allow Niall to pass, then followed behind. Grel, Niall observed, remained where he was. The young spider's mind took control of Niall's feet -- a gesture of courtesy -- steering him skillfully between thick strands of web that anchored overhead cobwebs to the floor. The recess itself was guarded by a curtain of webs that was virtually a miniature labyrinth. When they had steered their way between its overlapping sheets, Niall found himself standing in the entrance to a cave that extended back about twenty feet. To Niall's surprise, it seemed to be empty. Then, as they advanced toward its end, he realized that it turned a corner. Here the passage narrowed, and the ceiling became lower. Another turn brought them into a low-roofed chamber, not more than a dozen feet wide. Its walls were roughly carved, and glistened with moisture. Against the farther wall there was a low stone altar on which some roughly spherical object was lying. A young spider was crouched in front of it, his legs bunched under his body. For a moment, Niall assumed that this was the spider who might answer his question; then, as he rose to his feet, Niall realized that the spider was a mere child.

They approached the center of the chamber and halted. For a moment Niall found himself in complete darkness, as his guide abandoned telepathic contact; a moment later, the contact was renewed as Asmak entered the chamber. In that moment, Niall realized with a shock that the spherical object lying on the altar was the shriveled remains of a dead spider. It was lying on a kind of cushion made of tangled spider web; its withered legs looked like broken stalks, while the leathery body was devoid of the usual hairs, and was cracked and shiny with age, like brittle leather.

Asmak said: "You are in the presence of Cheb the Mighty." He lowered himself to the ground and, after a moment of indecision, Niall did the same.

Niall was in a state of bewilderment; he found it incredible that the great Spider Lord should be so small. According to legend, Cheb was a hundred-eyed monster who could bite a man in half with his enormous chelicerae. In fact, he was hardly larger than a domestic cat; even with his legs fully extended, he could hardly have stood more than three feet high.

After a few moments Asmak straightened up again and Niall did the same. He was fascinated by the sight of the Spider Lord. As a child, he had often shuddered when his grandfather, Jomar, told him stories about Cheb's cruelty and ferocity -- on one occasion he was said to have ordered the piecemeal execution of a thousand human beings, who were injected with spider venom to paralyze them, and then eaten over the course of several days. On another occasion Cheb had personally decapitated a hundred prisoners with his pincers. It was obvious that this story, at least, was untrue; Cheb's infolded pincers looked scarcely more than two inches long.

Asmak said: "Do you wish to speak directly to the Great One? Or do you wish me to speak on your behalf?"

Niall looked at him with amazement. "But how. . ." He had to make an effort not to stammer. "But surely the Great One is dead?"

"No, lord, he is not dead. Neither is he alive."

Niall stared at the mummified shell on the altar. "Not dead or alive? Surely that is impossible?"

In answer, Asmak conveyed another of those compressed bursts of information, which presented itself to Niall's mind as a kind of pictograph. Its content was so astonishing that Niall had to allow it to unfold slowly in order to absorb it. Asmak, it seemed, was being strictly accurate in saying that the Lord Cheb was neither alive nor dead. It was true that his body had been dead for many centuries; so had much of his brain. But the parts of the brain that stored information had been kept alive, so that Cheb's memory remained available to his own race, a kind of library preserved in the mummified shell of the body. Keeping his memory cells alive was a task assigned to young spiders; they prevented him from dying simply by feeding him with their own vital power. This was the explanation of the curious glow of warmth that Niall had experienced in the presence of the young spiders -- a glow whose nature combined respect and love. It was with this same living force that the spiders prevented Cheb's brain from dying.

Now, as Niall watched, the young spider reached into the brain of the Mighty Cheb, and poured forth a current of living energy. For the first time in his life, Niall understood a vital truth concerning the nature of love. He had always made the natural assumption that it was a mutually shared emotion. Now he recognized it as a vital force which existed in its own right, and which could be conveyed directly from one being to another in the form of a flow of life-energy.

What he found difficult to accept was that the shriveled corpse was in some sense alive. Niall's own telepathic sensitivity, amplified by the power of Asmak's mind, was unable to detect the slightest sign of life; the Lord Cheb might have been a piece of dead wood. The living current that flowed from the young spider was simply being absorbed, like water flowing into dry sand. What astonished Niall was that a spider who was obviously no more than a child was able to sustain such a stream of energy. Then, as he became more attuned to what was happening, he realized that the young spider was not alone in his efforts; he was a channel for the vital force of all the spiders gathered together in the cave. His task was to canalize and direct it, like a gardener directing the stream from a hose.

As Niall watched, the mummified body seemed to glow and expand; moments later, the stream of energy was literally rebounding, filling the narrow space of the cave with an unutterably joyous sense of springlike vitality -- a sensation that reminded him of the shimmering energy he had experienced among the plants and bushes near Skorbo's warehouse. Moments later, Niall realized that the Mighty Cheb was becoming aware of his surroundings. He almost expected to see him stir and stretch his legs, and the thought caused a momentary shock of alarm -- for the shriveled shell was obviously too frail to move without falling apart. It was a relief to realize, a moment later, that the body remained as dead as it had been five minutes ago. Only the mind was alive, and was contemplating its surroundings with curiosity, like someone who has awakened from a deep sleep.

Almost immediately, he became aware of Niall's presence. "Who is this?"

Asmak answered: "He is the chosen emissary of the great goddess."

The Lord Cheb surveyed Niall with a kind of cold curiosity, which reminded Niall of his first meeting with the present Death Lord.

"Is this true?"

Six months ago, that question would have filled Niall with nervous misgivings.

But in that time, he had become accustomed to the respect and obedience of the spiders.

Now he replied indifferently: "They tell me so."

"You seem little more than a child."

This seemed to require no reply, so Niall merely stood silently.

What had happened in this brief exchange was complex and yet strangely simple. Cheb had known human beings only as enemies or as slaves; therefore, he had never met anyone like Niall, who faced him without reverence or fear, and who seemed indifferent to whether he was believed or not. Moreover, Niall faced him as an equal, possibly a superior. Until Cheb addressed him, Niall had seen him through the eyes of Asmak and the other spiders, and shared their sense of reverence. But the moment Cheb spoke, Niall entered his consciousness. It was like looking another man in the eyes, and immediately assessing his character. Cheb's character was that of a ruler whose major traits are strength and cunning -- the cunning of one who has achieved power and intends to keep it. Compared with Asmak or Dravig, his mind lacked subtlety; he certainly lacked their intelligence. Yet he emanated a sense of potency; even his "voice" was masculine and dominant. Niall could understand why he was known as Cheb the Mighty. In his coarse way, he was the most powerful spider Niall had ever met.

It was plain that Cheb found this human alien puzzling. He was aware of Niall's intelligence, and accorded it a reluctant admiration. Yet he was also aware of Niall's immaturity and inexperience -- that if they had been face to face in the days when Cheb was alive, Niall would have been easy to outmaneuver. Therefore, the admiration was tinged with a patronizing disrespect. This shocked Asmak; and Cheb, in turn, was amused by Asmak's dismay. There was a sense, therefore, in which Niall and Cheb the Mighty met as equals, while the others were mere onlookers.

Cheb asked: "Why have you come here?"

"To ask you a question."

"Very well. Ask it."

"I want to know who built the great wall across the Valley of the Dead."

"I do not know. It was after my time."

This was a disappointment; and Niall could sense that Asmak was I also disappointed.

Cheb asked: "Is that all?"

"No. I have one more question."

"Ask it."

"Is it true that you were the first spider to understand the secrets of the human soul?"

There was a silence, then Cheb asked: "Who told you that story?"

"My grandfather." And since it was obvious that Cheb was waiting for further information, Niall went on: "He told me that a prince called Hallat had fallen in love with a maiden named Turool. But she was in love with a poor chieftain named Basat. The prince tried to kidnap her from Basat's camp, but a dog betrayed his presence by barking, and he was driven away. So -- according to my grandfather -- Hallat came to you, and offered to betray the secrets of the human soul in exchange for Turool. He taught you how to read the minds of human beings, and in exchange, your warriors descended on the camp of Basat, and captured it in a surprise attack by night. Prince Hallat executed Basat by striking off his head. But Turool became insane with grief, and sacrificed her life by attacking a spider, who killed her."

As he was speaking, Niall was aware that Cheb was listening with total attention.

And so, he realized a moment later, were Asmak and the young spider. Since it was obvious that they wanted him to go on, and since Niall had heard the story so often that he knew it by heart, he continued: "At this time, according to my grandfather, the spiders were already living in this city, and were curious to learn the secret of the white tower.

You offered to make Hallat the king of all men on Earth if he would help you to penetrate the secret of the tower. He agreed, and had many prisoners tortured to force them to reveal what they knew. Finally, an old woman agreed to tell him the answer to the riddle if he would spare her husband's life. She told him that the secret of the tower was a 'mind lock' -- the mind of man must interact with the walls of the tower, which would then dissolve away like smoke. This could be done with the aid of a magic rod. The old woman's husband possessed such a rod, for it was a symbol of his power as a chief.

Hallat took it from him, and went to the tower the next day at dawn -- for the old woman told him that the rays of the rising sun would fall on a secret door at the foot of the tower.

But when Hallat tried to approach the tower with the magic rod, some force threw him to the ground. He tried again, and the same thing happened. The third time, he stretched out both arms and shouted: 'I command you to open!' But when he tried to touch it with the magic rod, there was a flash like lightning, and Hallat was burned to a piece of black charcoal."

At this point Niall paused, having decided to tactfully omit the last lines of the story. But Cheb was obviously aware that there was more to come, and his manner made it clear that he was still waiting. Niall suppressed his embarrassment and went on: "When you heard what had happened, you had all the prisoners executed, including the old chief and his wife. And the mystery of the white tower remained unsolved." This time, Niall's manner made it clear that the story had come to an end. Yet the spiders remained silent for a long time. Finally, Cheb made a gesture that was amazingly like a human being shaking his head. Then he said: "You speak with the tongue of a sheevad."

"A sheevad?" It was the first time Niall had heard the expression.

Asmak explained: "A sheevad is one who speaks words of wisdom, like the Lord Dravig."

Niall was flattered but puzzled; as far as he could see, there was nothing particularly wise about his story. Then something about the attitude of the young spider brought a glimmer of understanding. He had been listening with the absorption of a child listening to a fairy tale. Niall was suddenly struck by the realization that the art of storytelling must be totally new to the spiders. When they "spoke" to one another, they did so in images which transmitted their meaning instantaneously. This meant, in turn, that there could be no "suspense"; the whole story, with its beginning and end, was transmitted in a single flash of information. When Cheb spoke of wisdom, he meant something more like "mind control," the ability to unfold an ordered sequence of images.

It was startling to realize that human language, for all its inbuilt limitations, struck the spiders, in some respects, as superior to their own method of communication.

Since Cheb was apparently absorbed in his own reflections, Niall cleared his throat and asked: "Is the story true?"

"True?" The Spider Lord seemed taken aback by the question. "Did Prince Hallat really exist?"

"A human being called Hallat certainly existed. But he was not a prince. He was a slave -- my slave."

"And did he teach you to understand the human soul?"

"No. But he taught me to understand human language."

"And how did that come about?" In asking such questions, Niall did not attempt to formulate them in words. For example, in asking if Hallat existed, he merely transmitted an image of Hallat with a general sense of interrogation. To ask how this came about, it was merely necessary to transmit a kind of question mark. Compared with spoken words, the method was pleasingly economical.

Unfortunately, Cheb's answer, couched in the same mode, was equally economical; it came as a bewildering explosion of information that outran Niall's powers of understanding, and left him feeling breathless. Cheb perceived his bewilderment, and in the spider mode -- which he obviously preferred to human language -- transmitted the message: "I am sorry. Let me try again."

His second attempt was less precipitate. The first image was of a bare, bleak landscape covered in snow, the next of spiders crouching in caves or ruined houses to escape the icy wind. These images were accompanied by a kind of background information -- like the background of a picture -- which Niall could either pay attention to or merely absorb as a part of the general effect.

Translated into human language, Cheb was saying, in effect: "When I was born, the world was suffering from a great ice age. Millions of my people died before they had reached adulthood. The snow fell day and night, and the wind changed continually so that shelter was almost impossible to find. The sky was always dark, and for a period of many years, no one saw the sun."

All this made it clear that Cheb was speaking of the period immediately after the Earth had been brushed by the tail of the comet Opik. Niall had learned of "the great winter" during his history lessons in the white tower. In the twenty-second century of the modern era, the Earth had been threatened with destruction by a radioactive comet, and most of the human race had left in giant space transports, to undertake the nine-year voyage -- at half the speed of light -- to a planet in the star system Alpha Centauri. The settlers christened this planet New Earth.

In fact, the head of the comet missed the Earth by more than a million miles. But material from its tail fell into the Earth's atmosphere, destroying nine-tenths of all animal life. And its gravitational field caused a perturbation in the moon's orbit, which in turn caused a violent outbreak of volcanic activity on Earth. The atmosphere turned into a kind of fog which formed an impenetrable barrier against the sunlight. The planet entered a new ice age, which continued until the dust particles slowly fell back to earth. Two centuries after the disaster, the ice fields began to retreat, as other climatic factors transformed the surface from a refrigerator into a hothouse.

The comet which had brought destruction also brought a new form of life. It originated on the planet Alpha-Lyrae 3, the third in the solar system of the blue star called Vega, in the constellation Lyra, twenty-seven light years away. On this planet, the force of gravity was so immense -- a hundred times greater than that of Earth -- that a man on its surface would have weighed ten tons and been unable to lift his eyelids. Under these conditions, the only intelligent life form to develop consisted of giant globular creatures, which on Earth would have been called vegetables.

A hundred and fifty million years ago, a fragment from an exploding galaxy passed through the Vega system, causing a catastrophic upheaval on Alpha-Lyrae 3, and tearing loose a segment almost as large as the Earth. This material was dragged through space in the wake of the star fragment until, many millions of years later, it came into near-collision with the comet Opik -- whose head was fifty thousand miles in diameter -- and was captured in its tail. This is how the seeds of the vegetable life form of the planet Alpha-Lyrae 3 came to land on Earth.

Some fell in deserts or polar regions and perished. Only five succeeded in germinating, and one of these was in the tropical region of the Great Delta. Because Earth's gravity was so much lower than that of their own planet, their molecular processes were accelerated, and they became immense -- the plant in the Great Delta, half-buried in the earth, looked like a small mountain.