One could detect the approach of a Master some way off. Their three round splayed feet made a distinctive flat slapping sound on the smooth hardness of the road. Now I heard this behind me as I passed under a lamp. It grew louder, since they moved faster than we did. I thought it might come abreast of me in the dark patch, and wanted to dodge away. But there was no side turning here, and, anyway, it might look suspicious. There was the possibility of losing touch with Fritz, as well. I walked on, remembering a few lines of poetry I had found in an old book at home:

  Like one, that on a lonesome road

  Doth walk in fear and dread,

  And having once turned round walks on,

  And turns no more his head;

  Because he knows a fearful fiend

  Doth close behind him tread.

  I had not turned round, but then I did not need to, knowing very well what it was that followed. We were in a part of the City entirely strange to me, and I suddenly realized that if I were questioned I had no sort of answer to give. I tried to think of one, but my brain had gone blank.

  The dark patch came, and the sounds were still behind me. He should have been up with me by now, I thought. I had a dreadful conviction that he had slowed his progress deliberately, that he was examining me and would accost me. I went on, expecting every moment that the Master's voice would boom out from behind, a tentacle, possibly, grasp me and swing me off the ground. I could see Fritz's figure dimly, fading into the darkness past the next light. The light itself was approaching. I wanted to strain my muscles into a lumbering run, but somehow kept to my resolution. The slapping footsteps were right behind me, much louder, it seemed, than I had ever heard them before. And then past, and I felt like collapsing in the weakness of relief.

  But more was to come. Fritz had already vanished into the next patch of darkness, and the Master disappeared in turn. I made my way after them. Light faded, leaving nothing but the distant glow. This brightened again. I could see the globe of the lamp, lifted on its long angular arm. And just beyond it...

  The Master was there, and so was Fritz. They stood together, the Master's tall shape towering over Fritz. I heard the distant sound of speech.

  I wanted to stop, to turn back into the shadows, but that might attract his attention. I had to go forward, whatever happened. And retreat would mean abandoning Fritz. I marched on. If he were in trouble...I did not think much of my chances of landing another punch like the one that had killed my own Master. I found myself trembling, with fear and resolution. Then, with a second surge of relief, I saw the Master move on and Fritz, more slowly, follow.

  He waited for me in the next shadows. I said, "What was it? What did he want to know?"

  Fritz shook his head. "Nothing. He thought he recognized me as the slave of someone he knew. I think he had a message to give. But I was not the one he wanted, so he went on."

  I drew a deep breath into the mask. "I thought we were sunk."

  "So did I."

  I could not see him in the darkness, but I could hear a tremor in his voice. I said, "Do you want to rest?"

  "No. We'll go on."

  An hour later we did rest. There was an open place with a large triangular garden pool, to one side of which trees something like weeping willows, only on a massive scale, drooped their branches down to the ground beside the pool, screening us, once we were inside their shelter, from the view of anyone who passed. Though in fact we had seen no one on the streets or ramps for some time now, and there was no sign of a Master in or near the pool. We stretched out under the ropy fronds that, although there was no wind or breeze in the City, from time to time brushed lightly against us. The ground pulled us down still, but it was bliss not to fight it, to lie flat and motionless. I would have liked to clear the inside of my mask of sweat, but even that discomfort was no more than a minor irritant.

  I said, "Have you been in this part of the City before, Fritz?"

  "Once only. We are not far from the edge."

  "And opposite where the river comes in?"

  "Roughly opposite."

  "So when we find the Wall, we can start looking for the outflow."

  "Yes. We shall have to be more careful from now on, of course. It is late to be on a night errand, and we are reaching the part where the Masters who have no slaves live. We must go more warily."

  "They don't seem to travel about at night, either."

  "No. That's lucky. But we can't be absolutely sure of it. Do you feel thirsty?"

  "A bit. Not much."

  "I do. It does no good to think about it, though. Since there are no slaves in this part of the City, there will be no communal places." He rose slowly to his feet. "I think we had better get on, Will."

  We saw strange things in our search. One of these was a vast pit, a triangle a hundred yards along each side, where, far down, green light gleamed on a seething viscous liquid in which, at intervals, bubbles slowly rose and popped. In another place there was a complicated structure of metal rods and catwalks looming up into the dark night, pointing, it seemed, to lights that flashed high above our heads. Once, turning a corner ahead of me, Fritz stopped, but beckoned me to come up with him. I did so quietly, and together we stared at the scene. It was a small garden pool, with only a few low-lying plants. In it were two Masters, the first we had seen since coming into this sector. They were locked together in what looked like deadly combat, tentacles interlaced, heaving against each other, the water turbulent with their struggling and rolling. We watched for a moment or two and then, making nothing of it, turned silently and went another way.

  In due course we reached the Wall. We came down a ramp between two small pyramids, and it was there. It stretched away on either side, golden even in the dim green light of the lamps, curving inward slightly as it was lost in the distance. The surface was smooth and hard and unbroken, offering not even a toe-hold, and upward as well as to the sides it showed no change as far as the eye could see. It was discouraging to look at it.

  I said, "Do you think we are near where the river ought to be?"

  I saw Fritz's thin ribs rise and fall in the lamp light. I was exhausted, but he much more so. He said, "We should be. But the river would be below ground."

  "Will there be a way of getting down to it?"

  "We must hope there is."

  I looked at the featureless Wall. "Which way do we go?"

  "It doesn't matter. Left. Do you hear anything?"

  "What?"

  "The sound of water."

  I listened intently. "No."

  "Nor do I." He shook his head, as though to rouse himself. "Left will do."

  Thirst began to attack me soon after. I tried to dismiss the thought, but it came back insistently. We were searching for water, after all. I thought of it, cold, crystal clear, like the streams that ran down below the White Mountains. The picture was a torment, but I could not put it out of my head.

  We investigated wherever there was a ramp leading down. We found ourselves in weird labyrinths, some piled high with crates, drums, metal spheres, and others packed with machinery that whined and hummed and sometimes sparked. Most of it was untended, but in one or two places there were two or three Masters doing things at boards covered with little holes and pimples. We were treading warily and softly, and they did not see us. In one great cavern gas bubbles were being made. They rolled out of the jaws of a machine down a sloping V-shaped channel and dropped into boxes, which, as they were full, closed themselves and were automatically moved away. In another place, even bigger, food was being manufactured. I recognized it, by the color and shape of the bubble bag, as being a kind of which my Master was especially fond. Had been fond, I corrected myself. The thought gave me a twinge of panic. Had the body been found yet? Were they already looking for his missing slave?

  Going back up a ramp to the surface, Fritz said, "I think left was wrong, perhaps. We have come a long way. We must turn back, and try in the other direction."

  "Rest first."
r />   "For a few minutes." He sounded discouraged. "We have not much time."

  So we plodded back along the way we had come, stopping every now and then to listen for the rushing sound of distant water, but hearing only the noise of the machines. We reached the point at which we had come to the Wall, and toiled on. I became aware of a difference, and looking up, saw the blackness of the night tinged behind us with faint green. The night was coming to an end. Dawn was breaking, and we were no nearer to finding a way out, no nearer to the elusive river.

  The day brightened. Thirst overrode hunger, but physical weakness seemed greater than either. The green globes winked out. We saw a Master in the distance, out in the street, and hid behind the edge of a garden pool until he had gone. A quarter of an hour later, we had to dodge two more. I said, "The streets may be swarming with them soon. We will have to give it up for tonight, Fritz, and get back to a place where we can take our masks off and eat and drink."

  "In a few hours they will find him."

  "I know. But what else can we do?"

  He shook his head, "I must rest."

  He lay down, and I lowered myself to lie beside him. I felt giddy with weakness, and thirst tore at my throat like a furious animal. Fritz seemed to be in a worse case still. At any rate, we could not stay here. I told him we ought to get up, but he did not answer. I got to my knees and pulled his arm. Then he said, his voice suddenly kindled with excitement, "I think...listen."

  I listened, and heard nothing. I told him so. He said, "Lie down and put your ear to the ground. Sound travels better that way. Listen!"

  I did and, after a moment, heard it: a thin rushing sound that might be the whisper of distant tumultuous waters. I pressed my ear closer to the surface of the road, hurting my face against the hardness of the mask. It was there, all right, a torrent underground. Thirst was sharpened even more by the tantalizing sound of it, but I felt I could ignore that, too. At last we had found the river. That is to say, we knew approximately where it was. The actual finding might take quite a bit longer.

  We tried systematically all the downward ramps in the area, testing them by listening to the ground. Sometimes the noise was louder, sometimes fainter. Once we lost it altogether, and had to cast back on our trail. There were avenues that were deceptively promising but that led to dead ends. More and more often we had to dodge Masters, or lie low till they had passed. One promising ramp led to a huge hall in which a score or more of them did things in front of benches: the river might well be somewhere at the far end, but we dared not go through. And time was passing; above ground we were in full day. Then, quite unexpectedly, we came on it.

  A very steep ramp, on which we found ourselves slipping and in danger of falling, led across a level space and dipped again, curving round on itself. Fritz clutched my arm and pointed. Ahead lay a cavern with a pointed roof, in which there were stacks of crates the height of a man. At the far end, only dimly visible in the light of the green globes that hung at intervals from the ceiling, water gushed from a huge hole and formed a pool, some fifty feet across.

  "Do you see?" Fritz asked. "The Wall."

  It was true. At the end of the cavern, beyond the pool, was the dull gleam of gold, unmistakably the inner surface of the barrier that ringed the City, and on which the great dome rested. The pool frothed against it. The water gushing in was that which had circulated through the City, the waste and overflow of hundreds of garden pools. Steam rose up from it. It filled the pool, and from the pool...It must go out, under the Wall: there could be no other explanation.

  Cautiously we made our way along the cavern, between the stacked crates, to the edge of the pool. There were things like vertical nets in the water, and we saw also that the water steamed only at its entry point. Nearer to the Wall, Fritz reached down and put a hand in it.

  "It is quite cool here. The nets must take the heat out, so it is not lost to the City." He stared down into the churning depths, green from the lamps hanging over them. "Will, let the current take you. Before you go, I will put sealer on the air vents of your mask. There is enough air inside a mask to give you five minutes breathing. I have tried this out."

  What he called "sealer" was a substance the Masters used for closing containers that had been opened. It came out of a tube liquid, but dried and hardened almost right away.

  I said, "I'll do yours first."

  "But I am not coming."

  I stared at him. "Don't be silly. You must."

  "No. They must not suspect anything."

  "But they'll do that when they find I've gone."

  "I do not think so. Your Master died from a fall, an accident. What would a slave do, then? I think he might go to the Place of Happy Release, because there is no point in him going on living."

  I saw the force of the argument, but said dubiously, "They might think that, but we can't be sure."

  "We can help them to think it. I know some of the slaves in your pyramid. If I tell one that I saw you, and you said that was where you were going..."

  I saw that, too. Fritz had worked things out very well. I said, "If you escaped, and I went back..."

  He said patiently, "It would not help, would it? It is your Master that is dead, not mine -- you who should go to the Place of Happy Release. If you go back, they will question you. It would be fatal."

  "I don't like it," I said.

  "It doesn't matter what you like, or I like. One of us must get away to take the news of what we have learned back to Julius and the others. It is safer if it is you." He squeezed my arm. "I will get out. It is easy now that I know where the river is. In three days, I will tell the other slaves in my pyramid that I am too sick to work, and therefore have chosen the Happy Release. I will hide out of the way, and come down here at night."

  I said, "I will wait for you outside."

  "Wait three days, no longer. You must get back to the White Mountains before winter sets in. And now you must hurry." He forced a smile. "The sooner you dive, the sooner I can get back, and have a drink of water."

  He spread the sealer on the air vents of my mask, after first telling me to take a deep breath. In a few seconds he nodded, indicating the seal was hard. He pressed my arm again and said, "Good luck." The sound was fainter, more muffled than usual.

  I dared delay no longer. The surface of the pool was about six feet below the top of the low containing wall. I climbed up on this and dived down, deep down, into the swirling waters.

  11 -- Two Go Home

  Down, down, into darkness. The current tugged me, and I went with it, pulling myself through the water in a crude and feeble attempt at swimming. I swam forward as well as down. My hand touched something and, as my shoulder banged painfully against it, I knew I was at the Wall. But still unbroken, with no sign of an opening, and the current still dragging down.

  Possibilities and fears crowded in on me. The water might flow out through gratings, which I would be unable to remove. Or there might be more nets, and I would tangle myself in them. The whole enterprise seemed hopeless. There was a pressure of air in my lungs, the beginning of a roaring in my head. I breathed out a little, and drew a small breath of air in. Five minutes, Fritz had said. How long had I been under already? I realized that I had no idea; it might be ten seconds, or ten times that. Panic, the fear of drowning, clutched me, and I wanted to turn and swim back up, against the pull of water, up to the surface where I had left Fritz.

  I swam on and down, trying to blank my mind to everything but the need to hold on. If I abandoned things now we were lost, anyway. And we must not lose. One of us had to get through. Far above me there was a dim green radiance, but darkness was all round and below me, and I was diving deeper into it. I took another shallow breath, to ease my aching lungs. I wondered if I were already past the point of no return. Then there was turbulence, the current breaking up and changing direction. I reached forward, but there was still an impassible solidity. Down, down...An edge, an opening. The tide carried me into it and I realized t
hat now, finally, I was committed. The current was stronger, more closely channeled. I had to go on because there was no hope of getting back.

  So I swam and was carried along, in utter blackness. I took shallow breaths when I felt I must. Time, as it passed, became more and more immeasurable. There was a sense of having been hours down here, not minutes. Occasionally I bumped my head against the hard surface above me; if I swam down a few feet I could touch the bottom of the conduit. Once my outstretched hand brushed against a side wall, but I was too concerned with getting through to want to establish how wide it might be.