"Then men shattered their spores and emerged. They were intelligent, active. And they were gifted with a trait, a character, possessed by no other creature in this world.

Not even the savage Eaters had it. Men organized us to exterminate the Eaters and therein lay the difference. Men had initiative. We have the word now, which you gave us, and we apply it, but we still do not know what the thing is that it labels."

"You fought beside us," Lavon said.

"Gladly. We would never have thought of that war by ourselves, but it was good and brought good. Yet we wondered. We saw that men were poor swimmers, poor walkers, poor crawlers, poor climbers. We saw that men were formed to make and use tools, a concept we still do not understand, for so wonderful a gift is largely wasted in this universe, and there is no other. What good are tool-useful members such as the hands of men? We do not know. It seems plain that so radical a thing should lead to a much greater rulership over the world than has, in fact proven to be possible for men."

Lavon's head was spinning. "Para, I had no notion that you peop16 were philosophers."

"The protos are old," Shar said. He had again turned to look out the window, his hands locked behind his back. "They aren't philosopher Lavon, but they are remorseless logicians. Listen to Para."

"To this reasoning there could be but one outcome," the Para said. "Our strange ally, Man, was like nothing else in this universe. He and is ill-fitted for it. He does not belong here; he has been-adapted. This drives us to think that there are other universes besides this one, but where these universes might lie, and what their properties might be, it is impossible to imagine. We have no imagination, as men know."

Was the creature being ironic? Lavon could not tell. He said slowly: "Other universes? How could that be true?"

"We do not know," the Para's uninflected voice hummed. Lavon waited, but obviously the proto had nothing more to say.

Shar had resumed sitting on the window sill, clasping his knees, watching the come and go of dim shapes in the lighted gulf, "It is quite true/' he said. "What is written on the remaining plates makes it plain. Let me tell you now what they say.

"We were made, Lavon. We were made by men who are not as we are, but men who were our ancestors all the same. They were caught in some disaster, and they made us, and put us here in our universe-so that, even though they had to die, the race of men would live."

Lavon surged up from the woven spyrogrya mat upon which he had been sitting.

"You must think I'm a fool!" he said sharply.

"No. You're our Lavon; you have a right to know the facts. Make what you like of them." Shar swung his webbed toes back into the chamber. "What I've told you may be hard to believe, but it seems to be so; what Para says backs it up. Our unfitness to live here is self-evident. I'll give you some examples: "The past four Shars discovered that we won't get any further in our studies until we learn how to control heat. We've produced enough heat chemically to show that even the water around us changes when the temperature gets high enough. But there we're stopped."

"Why?" "Because heat produced in open water is carried off as rapidly as it's produced.

Once we tried to enclose that heat, and we blew up a whole tube of the castle and killed everything in range; the shock was terrible, "e measured the pressures that were involved in that explosion, and we discovered that no substance we know could have resisted them. Theory suggests some stronger substances-but we need heat to form them!

"Take our chemistry. We live in water. Everything seems to dissolve in water, to some extent. How do we confine a chemical test to the crucible we put it in? How do we maintain a solution at one dilution? I don't know. Every avenue leads me to the same stone door. We're thinking creatures, Lavon, but there's something drastically wrong in the ay we think about this universe we live in. It just doesn't seem to lead to results"

Lavon pushed back his floating hair futilely. "Maybe you're thinking about the wrong results. We've had no trouble with warfare, or crops, or practical things like that. If we can't create much heat, well, most of us won't miss it; we don't need any.

What's the other universe supposed to be like, the one our ancestors lived in? Is it any better than this one?"

"I don't know," Shar admitted. "It was so different that it's hard to compare the two. The metal plates tell a story about men who were traveling from one place to another in a container that moved by itself. The only analogy I can think of is the shallops of diatom shells that our youngsters use to sled along the thermocline; but evidently what's meant is something much bigger.

"I picture a huge shallop, closed on all sides, big enough to hold many people- maybe twenty or thirty. It had to travel for generations through some kind of space where there wasn't any water to breathe, so that the people had to carry their own water and renew it constantly. There were no seasons; no yearly turnover; no ice forming on the sky, because there wasn't any sky in a closed shallop; no spore formation.

"Then the shallop was wrecked somehow. The people in it knew they were going to die. They made us, and put us here, as if we were their children. Because they had to die, they wrote their story on the plates, to tell us what had happened. I suppose we'd understand it better if we had the plate Shar III lost during the war, but we don't."

"The whole thing sounds like a parable," Lavon said, shrugging. "Or a song. I can see why you don't understand it. What I can't see is why you bother to try."

"Because of the plates," Shar said. "You've handled them yourself, so you know that we've nothing like them. We have crude, impure metals we've hammered out, metals that last for a while and then decay. But the plates shine on and on, generation after generation. They don't change; our hammers and graving tools break against them; the little heat we can generate leaves them unharmed. Those plates weren't formed in our universe-and that one fact makes every word on them important to me. Someone went to a great deal of trouble to make those plates indestructible to give them to us. Someone to whom the word 'stars' was important enough to be worth fourteen repetitions, despite the fact that the word doesn't seem to mean anything. I'm ready to think that if our makers repeated the word even twice on a record that seems likely to last forever, it's important for us to know what it means."

"All these extra universes and huge shallops and meaningless words-I can't say that they don't exist, but I don't see what difference it makes. The Shars of a few generations ago spent their whole lives breeding better algae crops for us, and showing us how to cultivate them, instead of living haphazardly off bacteria. That was work worth doing. The Lavons of those days evidently got along without the metal plates, and saw to it that the Shars did, too: Well, as far as I'm concerned, you're welcome to the plates, if you like them better than crop improve- ment, but I think they ought to be thrown away."

"All right," Shar said, shrugging. "If you don't want them, that ends the traditional interview. We'll go our-"

There was a rising drone from the table-top. The Para was lifting itself, waves of motion passing over its cilia, like the waves which went across the fruiting stalks of the fields of delicate fungi with which the bottom was planted. It had been so silent that Lavon had forgotten it; he could tell from Shar's startlement that Shar had, too.

"This is a great decision," the waves of sound washing from the creature throbbed.

"Every proto has heard it and agrees with it. We have been afraid of these metal plates for a long time, afraid that men would learn to understand them and to follow what they say to some secret place, leaving the protos behind. Now we are not afraid."

"There wasn't anything to be afraid of," Lavon said indulgently.

"No Lavon before you had said so," Para said. "We are glad. We will throw the plates away."

With that, the shining creature swooped toward the embrasure. With it, it bore away the remaining plates, which had been resting under it on the table-top, suspended delicately in the curved tips of its supple cilia. With a cry, Shar plunged through the water toward the opening.

"Stop, Para!"

But Para was already gone, so swiftly that he had not even heard the call. Shar twisted his body and brought up on one shoulder against the tower wall. He said nothing. His face was enough. Lavon could not look at it for more than an instant.

The shadows of the two men moved slowly along the uneven cobbled floor. The Noc descended toward them from the vault, its single thick jentacle stirring the water, its internal light flaring and fading irregularly. It, too, drifted through the window after its cousin, and sank slowly away toward the bottom. Gently its living glow dimmed, flickered, winked out.

II.

For many days, Lavon was able to avoid thinking much about the loss. There was always a great deal of work to be done. Maintenance of the Castles, which had been built by the now-extinct Eaters, was a never-ending task. The thousand dichotomously branching wings tended to crumble, especially at their bases where they sprouted from each other, and no Shar had yet come forward with a mortar as good as the rotifer-spittle which had once held the together. In addition, the breaking through of windows and the construe tion of chambers in the early days had been haphazard and often un sound. The instinctive architecture of the rotifers, after all, had not been meant to meet the needs of human occupants.

And then there were the crops. Men no longer fed precariously upon passing bacteria; now there were the drifting mats of specific water- fungi, rich and nourishing, which had been bred by five generations of Shars. These had to be tended constantly to keep the strains pure, and to keep the older and less intelligent species of the protos from grazing on them. In this latter task, to be sure, the more intricate and farseeing proto types cooperated, but men were needed to supervise.

There had been a time, after the war with the Eaters, when it had been customary to prey upon the slow-moving and stupid diatoms, whose exquisite and fragile glass shells were so easily burst, and who were unable to learn that a friendly voice did not necessarily mean a friend. There were still people who would crack open a diatom when no one else was looking, but they were regarded as barbarians, to the puzzlement of the protos. The blurred and simple-minded speech of the gorgeously engraved plants had brought them into the category of pets- a concept which the protos were utterly unable to grasp, especially since men admitted that diatoms on the half-frustrule were delicious.

Lavon had had to agree, very early, that the distinction was tiny. After all, humans did eat the desmids, which differed from the diatoms only in three particulars: their shells were flexible, they could not move, and they did not speak. Yet to Lavon, as to most men, there did seem to be some kind of distinction, whether the protos could see it or not, and that was that. Under the circumstances he felt that it was a part of his duty, as a leader of men, to protect the diatoms from the occasional poachers who browsed upon them, in defiance of custom, in the high levels of the sunlit sky.

Yet Lavon found it impossible to keep himself busy enough to forge that moment when the last clues to Man's origin and destination ha been seized and borne away into dim space.

It might be possible to ask Para for the return of the plates, explain that a mistake had been made. The protos were creatures of implacable logic, but they respected Man, were used to illogic in Man, and might reverse their decision if pressed- We are sorry. The plates were carried over the bar and released the gulf. We will have the bottom there searched, but...

With a sick feeling he could not repress, Lavon knew that when rotos decided something was worthless, they did not hide it in some chamber like old women. They threw it away-efficiently.

Yet despite the tormenting of his conscience, Lavon was convinced that the plates were well lost. What had they ever done for man, except to provide Shars with useless things to think about in the late seasons of their lives? What the Shars themselves had done to benefit Man, here, in the water, in the world, in the universe, had been done by direct experimentation. No bit of useful knowledge ever had come from the plates.

There had never been anything in the plates but things best left unthought. The protos were right.

Lavon shifted his position on the plant frond, where he had been sitting in order to overlook the harvesting of an experimental crop of blue-green, oil-rich algae drifting in a clotted mass close to the top of the sky, and scratched his back gently against the coarse bole. The protos were seldom wrong, after all. Their lack of creativity, their inability to think an original thought, was a gift as well as a limitation. It allowed them to see and feel things at all times as they were-not as they hoped they might be, for they had no ability to hope, either.

"La-von! Laavah-on!"

The long halloo came floating up from the sleepy depths. Propping one hand against the top of the frond, Lavon bent and looked down. One of the harvesters was looking up at him, holding loosely the adze with which he had been splitting free the glutinous tetrads of the algae.

"Up here. What's the matter?"

"We have the ripened quadrant cut free. Shall we tow it away?"

"Tow it away," Lavon said, with a lazy gesture. He leaned back again. At the same instant, a brilliant reddish glory burst into being above him, and cast itself down toward the depths like mesh after mesh f the finest-drawn gold. The great light which lived above the sky during the day, brightening or dimming according to some pattern no ahar ever had fathomed, was blooming again.

Few men, caught in the warm glow of that light, could resist looking up at it- especially when the top of the sky itself wrinkled and smiled just a moment's climb or swim away. Yet, as always, Lavon's bemused upward look gave him back nothing but his own distorted. bobbling action, and a reflection of the plant on which he rested.

Here was the upper limit, the third of the three surfaces of the universe. The first surface was the bottom, where the water ended.

The second surface was the thermocline, the invisible division between the colder waters of the bottom and the warm, light waters of the sky. During the height of the warm weather, the thermocline was definite enough a division as to make for good sledding and for chilly passage. A real interface formed between the cold, denser bottom waters and th warm reaches above, and maintained itself almost for the whole of the warm season.

The third surface was the sky. One could no more pass through that surface than one could penetrate the bottom, nor was there any better reason to try. There the universe ended. The light which played over it daily, waxing and waning as it chose, seemed to be one of its properties Toward the end of the season, the water gradually grew colder and more difficult to breathe, while at the same time the light became duller and stayed for shorter periods between darknesses. Slow currents started to move. The high waters turned chill and began to fall. The bottom mud stirred and smoked away, carrying with it the spores of the fields of fungi. The thermocline tossed, became choppy, and melted away. The sky began to fog with particles of soft silt carried up from the bottom, the walls, the corners of the universe. Before very long, the whole world was cold, inhospitable, flocculent with yellowing, dying creatures.

Then the protos encysted; the bacteria, even most of the plants and, not long afterward, men, too, curled up in their oil-filled amber shells. The world died until the first tentative current of warm water broke the winter silence.

"La-von!"

Just after the long call, a shining bubble rose past Lavon. He reached out and poked it, but it bounded away from his sharp thumb. The gas-bubbles which rose from the bottom in late summer were almost invulnerable -and when some especially hard blow or edge did penetrate them, they broke into smaller bubbles which nothing could touch, and fled toward the sky, leaving behind a remarkably bad smell.

Gas. There was no water inside a bubble. A man who got inside a bubble would have nothing to breathe.

But, of course, it was impossible to penetrate a bubble. The surface tension was too strong. As strong as Shar's metal plates. As strong as the top of the sky.

As strong as the top of the sky. And above that-once the top was broken-a world of gas instead of water? Were all worlds bubbles of water drifting in gas?

If it were so, travel between them would be out of the question, since it would be impossible to pierce the sky to begin with. Nor did infant cosmology include any provisions for Bottoms for the worlds.

And yet some of the local creatures did burrow into the bottom, quite , epjy; seeking something in those depths which was beyond the reach f Man. Even the surface of the ooze, in high summer, crawled with tiny creatures for which mud was a natural medium. Man, too, passed freely between the two countries of water which were divided by the thermocline, though many of the creatures with which he lived could not pass that line at all, once it had established itself.

And if the new universe of which Shar had spoken existed at all, it had to exist beyond the sky, where the light was. Why could not the sky be passed, after all? The fact that bubbles could be broken showed that the surface skin that formed between water and gas wasn't completely invulnerable. Had it ever been tried? Lavon did not suppose that one man could butt his way through the top of the sky, any more than he could burrow into the bottom, but there might be ways around the difficulty. Here at his back, for instance, was a plant which gave every appearance of continuing beyond the sky: its uppermost fronds broke off and were bent back only by a trick of reflection.

It had always been assumed that the plants died where they touched the sky. For the most part, they did, for frequently the dead extension could be seen, leached and yellow, the boxes of its component cells empty, floating imbedded in the perfect mirror. But some were simply chopped off, like the one which sheltered him now.

Perhaps that was only an illusion, and instead it soared indefinitely into some other place-some place where men might once have been born, and might still live ...

The plates were gone. There was only one other way to find out.

Determinedly, Lavon began to climb toward the wavering mirror of the sky. His thorn-thumbed feet trampled obliviously upon the clustered sheaves of fragile stippled diatoms. The tulip-heads of Vortae, placid and murmurous cousins of Para, retracted startledly out of his way upon coiling stalks, to make silly gossip behind him. Lavon did not hear them. He continued to climb doggedly toward the light, his fingers and toes gripping the plant-bole.

"Lavon! Where are you going? Lavon!"

He leaned out and looked down. The man with the adze, a doll-like figure, was beckoning to him from a patch of blue-green retreating over a violet abyss. Dizzily he looked away, clinging to the bole; he had never been so high before. Then he began to climb again, breathless.

After a while, he touched the sky with one hand. He stopped to breathe. Curious bacteria gathered about the base of his thumb where blood from a small cut was fogging away, scattered at his gesture, and wriggled mindlessly back toward the dull red lure.

He waited until he no longer felt winded, and resumed climbing. The sky pressed down against the top of his head, against the back of his neck, against his shoulders. It seemed to give slightly, with a tough frictionless elasticity. The water here was intensely bright, and quite colorless. He climbed another step, driving his shoulders against that enormous weight.

It was fruitless. He might as well have tried to penetrate a cliff.

Again he had to rest. While he panted, he made a curious discovery. All around the bole of the water plant, the steel surface of the sky curved upward, making a kind of sheath. He found that he could insert his hand into it-there was almost enough space to admit his head as well. Clinging closely to the bole, he looked up into the inside of the sheath, probing with his injured hand. The glare was blinding.

There was a kind of soundless explosion. His whole wrist was suddenly encircled in an intense, impersonal grip, as if it were being cut in two. In blind astonishment, he lunged upward.

The ring of pain traveled smoothly down his upflung arm as he rose, was suddenly around his shoulders and chest. Another lunge and his knees were being squeezed in the circular vine. Another- Something was horribly wrong. He clung to the bole and tried to gasp, but there was-nothing to breathe.

The water came streaming out of his body, from his mouth, his nostrils, the spiracles in his sides, spurting in tangible jets. An intense and fiery itching crawled over the entire surface of his body. At each spasm, long knives ran into him, and from a great distance he heard more water being expelled from his book-lungs in an obscene, frothy sputtering. Lavon was drowning.

With a final convulsion, he kicked himself away from the splintery bole, and fell.

A hard impact shook him; and then the water, which had clung to him so tightly when he had first attempted to leave it, took him back with cold violence.

Sprawling and tumbling grotesquely, he drifted, down and down an down, toward the bottom.

III.

For many days, Lavon lay curled insensibly in his spore, as if in the winter sleep.

The shock of cold which he had felt on reentering native universe had been taken by his body as a sign of coming winter as it had taken the oxygen-starvation of his brief sojourn above the sky. The spore-forming glands had at once begun to function.

Had it not been for this, Lavon would surely have died. The danger of drowning disappeared even as he fell, as the air bubbled out of his lungs and readmitted the life- giving water. But for acute dessication and third degree sunburn, the sunken universe knew no remedy. The healing amnionic fluid generated by the spore-forming glands, after the transparent amber sphere had enclosed him, offered Lavon his only chance.

The brown sphere was spotted after some days by a prowling ameba, quiescent in the eternal winter of the bottom. Down there the temperature was always an even 4, no matter what the season, but it was unheard of that a spore should be found there while the high epilimnion was still warm and rich in oxygen.

Within an hour, the spore was surrounded by scores of astonished protos, jostling each other to bump their blunt eyeless prows against the shell. Another hour later, a squad of worried men came plunging from the castles far above to press their own noses against the transparent wall. Then swift orders were given.

Four Para grouped themselves about the amber sphere, and there was a subdued explosion as the trichocysts which lay embedded at the bases of their cilia, just under the pellicle, burst and cast fine lines of a quickly solidifying liquid into the water. The four Paras thrummed and lifted, tugging.

Lavon's spore swayed gently in the mud and then rose slowly, entangled in the web. Nearby, a Noc cast a cold pulsating glow over the operation-not for the Paras, who did not need the light, but for the baffled knot of men. The sleeping figure of Lavon, head bowed, knees drawn up to its chest, revolved with an absurd solemnity inside the shell as it was moved.

"Take him to Shar, Para."

The young Shar justified, by minding his own business, the traditional wisdom with which his hereditary office had invested him. He observed a once that there was nothing he could do for the encysted Lavon which would not be classifiable as simple meddling.

He had the sphere deposited in a high tower room of his castle, where there was plenty of light and the water was warm, which should suggest to the hibernating form that spring was again on the way. Beyond that, he simply sat and watched, and kept his speculations to himself.

Inside the spore, Lavon's body seemed rapidly to be shedding its skin, in long strips and patches. Gradually, his curious shrunkenness disappeared. His withered arms and legs and sunken abdomen filled out again.

The days went by while Shar watched. Finally he could discern no more changes, and, on a hunch, had the spore taken up to the topmost battlements of the tower, into the direct daylight.

An hour later, Lavon moved in his amber prison. He uncurled and stretched, turned blank eyes up toward the light. His expression was that of a man who had not yet awakened from a ferocious nightmare. His whole body shone with a strange pink newness.

Shar knocked gently on the wall of the spore. Lavon turned his blind face toward the sound, life coming into his eyes. He smiled tentatively and braced his hands and feet against the inner wall of the shell.

The whole sphere fell abruptly to pieces with a sharp crackling. The amnionic fluid dissipated around him and Shar, carrying away with it the suggestive odor of a bitter struggle against death.

Lavon stood among the bits of shell and looked at Shar silently. At last he said: "Shar-I've been beyond the sky."

"I know," Shar said gently.

Again Lavon was silent. Shar said, "Don't be humble, Lavon. You've done an epoch-making thing. It nearly cost you your life. You must tell me the rest-all of it."

"The rest?"