She raised her hand to throw her features into the shadows, and she said, "Please, Jack! Take me back up! Please! I'm so scared. Listen. . ."

She hesitated, then said, softly, "I'll do anything you want. Anything."

"Anything?"

"Anything."

"No," he said. "Not even for the chance to make you suffer. I'm on the trail of something even more desirable than revenge."

"You b.a.s.t.a.r.d!" she said. "I hate your slimy guts! Forget about what I said. And don't ever try to touch me; you make my flesh crawl."

"Then," he said evenly, though it cost him much effort, "you wouldn't have done everything I wanted. For I wanted you to love me; I wanted you to give yourself willingly, gladly, eagerly to me, and to enjoy doing it. But I should have known better. That is one thing you can't possibly do, even if you wanted to."

She did not reply. Cull turned away from her. Fyodor gave a little cry and said, "We're not far from our destination! Here's the outer wall of a cool-air shaft. Feel it. If I'm not mistaken, the House is right next to it."

"What's your plan?" Cull asked.

"Obviously, there's no entrance along this walk. So, we must go below. If there's an en-trance, it has to be further down."

"If?" said Cull. "You've brought me to this stinking lousy place on an if?"

"There has to be an entrance down there! Otherwise, how do they get supplies? X and his aides never leave the House except to pick up the dead. Don't tell me they just live there. The House is too small for them to be cooped up in all the time. Follow me. I know where the downward en-trance is, but I've never had the courage to take it. Now, I've someone with me."

"A poor subst.i.tute for courage," Cull said. "How can the lack of something fill a void?"

Around the vast curve they walked until the curve began to straighten out. Here, in the middle of the walk, was a hole just wide enough for a man with a pack on his back to insert himself. In the middle of the tube leading down from the hole was a white metal pole. Cull put his hands around the pole, and his fingertips almost met. The metal looked dry but felt greasy.

"Like a fireman's pole," he said. "Where does it lead to? The fire?"

The light of his torch illuminated the tube downward for some distance. He could see no bot-tom, but there must be one to support the base of the pole. Or must there?

"Easy to get down," he said. "How do we get back up? We might not be strong enough to haul ourselves up hand over hand. And the pole's slick."

"We can always brace ourselves against the wall of the tube," Fyodor said. "Don't you see that this confirms my theory? If it is so hard to get back up the pole, then those who go down must have another way to get back up...."

"Perhaps. You first."

Fyodor sat down on the edge of the tube and ex-tended his legs to reach the other side. He scooted forward until his b.u.t.tocks slid off the edge and down into the opening. His knees went upward as his legs bent to give him room to fit into the tube.

"I have to hold the torch with one hand and the pole with the other," he said. "But I can't brace myself with my back against the side because I'd make the pack on my back ride up too high. Might tear it off. So, I'll just have to trust to one hand to hold me."

"You can't," Cull said. "Don't be a d.a.m.n fool."

He lit another torch and dropped it between Fyodor's legs. The torch fell without turning over, the heavy flaming downward end holding it steady. The walls near them lit up, then darkened as the torch plunged away and became smaller, smaller.

"How far down?" Cull said.

"Who knows? Only one way to tell."

The torch, now a tiny spark, suddenly went out. Whether it had struck bottom and rolled to one side and out of sight, or whether it had fallen so far they just could not see it, Cull did not know. As Fyodor said, there was only one way. Down.

Fyodor slid on down, holding to the pole with one hand, the other holding a torch, and his legs wrapped around the pole. Awkwardly, Cull grabbed the pole. "You coming?" he said to Phyllis without turning his head. Her voice was shaky, but her words were brave. "I can go any place you can, jackal.

And a lot farther."

He smiled slightly, and he slid down the pole. Fortunately, it had a slick feeling; there did not seem to be much friction. Of course, there was some. Otherwise, they would have shot down like express trains, unable to hold themselves back. But there wasn't enough friction to burn legs and hand, just enough so they could hold back with a tight squeeze and journey downward at a fair rate of speed. It seemed a long time until he reached bottom.

Actually, it took about ninety seconds, if his rate of counting was correct. He found Fyodor waiting for him, holding his torch high and peering around. The light showed more tunnels and ca.n.a.ls, just like those above. The torch he'd dropped was nowhere in sight. He presumed it had bounced off the walk and dropped into the sewage, just six feet below.

"The air got cooler as we came down," he said. "Feel that draft? And where's the stink?"

"Maybe we're used to it by now," said Fyodor.

"No, it's been replaced by a perfume. Can't you smell it?"

Fyodor shook his head. "I never did have much of a nose. I'm odordeaf, if you will pardon the term."

He wasn't deaf to sound. He reacted just as quickly as Cull did to the vast bellow.

"G.o.d's sake!" Cull gasped. "What is it? Where. . .?"

"That way, I think," said Fyodor, pointing with his free hand down the tunnel behind Cull. His hand shook. He shook all over; his teeth chat-tered. Phyllis clung to the pole.

''Let's go the other way," Cull said.

Another bellow boomed along the tunnel. This one came from the opposite direction in which Fyodor had pointed.

Cull dropped the torch, pushed Phyllis so hard she sprawled on the floor, leaped upward and grabbed the pole. Surprisingly, the pole now felt dry; it furnished a good grip. He swarmed upward for about twenty feet, then stopped to look down. Fyodor was not following him but was standing beside the pole and looking up the shaft.

"Now that you know you can get back up easily," he said, "why don't you come back down?"

"Didn't you hear that?"

"I'm not going to quit now. If you quit, I'm going on alone. But I'd feel much better, braver, if you were with me."

Cull didn't know why he did not keep on climbing. He didn't really care about Fyodor's opinion of him. Perhaps he was scared of going back to the surface alone. Or his curiosity may have been stronger than fear. He knew he'd never be satisfied unless he found out what was going on in the bowels of this world. So he slid back. And noted, as he did, that the pole became slick. Bipolarity of lubrication.

Phyllis was on her feet again and holding her torch. After one glance at her scorn, he turned away.

Fyodor leading, they went along the tunnel, which begame wider with every few steps. Soon, the torches could not penetrate far enough for them to distinguish the other side. Suddenly, they were standing on a narrow ledge. About twenty feet below, a black sluggish river moved. Bubbles arose from its depths. Then, a bubble, larger than all the rest put together, rose. It was followed by a head.

The head was about six times as large as Cull's -- a slanting forehead and no hair and four elephantine ears, two enormous black eyes. No nose. The mouth was broad, thick-lipped, and open, revealing a row of tigerlike teeth and two curving canines. The tongue ran out, seemingly endless, and its tip finally fell into the water. And they saw that the tongue was covered with hun-dreds of tiny sharp teeth.

It was a demon, for the eyes shone in the torchlight as it turned its head.

Cull didn't know how deep the river was or how tall the monster might be. It was possible that it could jump out of the water, seize the edge of the walk, and pull itself up on to the walk.

Just as he thought of that, the demon lifted its right hand out of the water. Rather, it was not a hand but a paw. The paw held a human leg. While they watched, the paw dropped the leg onto the tongue, and the tongue began running back into the mouth until it was well within the cavern of the mouth.

Then, the lips closed, and there was a crunching as the lower jaw began grinding. The eyes, at least six inches wide, stared upward at them. They seemed to say, Next?

Slowly, the three human beings began to move away, walking sideways while they watched it, afraid to take their eyes off it. They could have run, but there was nothing to keep it from swim-ming along in place with them, for the walk and the river followed the same tunnel.

"Maybe that leg belongs to the demon we were chasing," said Fyodor in a very low voice.

"Demon eats demon. A demon will eat anybody or anything, given a chance."

"Let's not give it a chance," Cull whispered. He kept edging away. Suddenly, the monster opened its mouth and bellowed with laughter. Laughter! That was all that was needed. Panic overwhelmed them and they ran until their lungs burned; they sobbed, and their legs were turned into the jelly of utter fatigue.

Then, sitting down, breaths soughing, they looked back along the oily water. No sign of the demon. But he could be under the surface just below them.

When Fyodor's panting had slowed enough for him to gasp out words, he said, "Demons have to eat. And there can't be enough human flesh available for them. So. . ."

He pointed at some excrement floating by, and said, "I think they must be scavengers. Keep the sewage fairly clean, anyway."

He was, Cull supposed, right. But that didn't lessen the danger.

Later, he knew that it wasn't only demons that performed in these tunnels as sparrows, vultures, jackals, hyenas. They had resumed walking for about two miles when they heard voices. There was only one thing to do, keep going toward the source of the voices, which was ahead. And presently, they were looking down on four human beings(?) standing in water up to their chests. Two men, two women. All holding their hands over their eyes against the glare of the torches.

Near them, about fifty yards away, was the first of the many islands they were to see in the river.

This was an oval flat-topped island of the same greyish metal as the tunnel. It was fifty feet across and rose from the surface to a height of about a foot.

What set Cull quivering was the thought that the fate of these people might be his. Had they, too, climbed into the sewers to discover what mysteries they held? And had they been unable to get out, become lost, been forced to live in the dark and to eat whatever was nourishing, if nauseating, that came along to them by the bounty of the sewage? Was this to be his doom?

No, he swore, I'd drown myself in the river, fill my lungs with that loathsome clotted water before I'd become like them. Blind gropers for c.r.a.p to eat, wet and shivering, stinking and half-sick.

But what if theyhad drowned themselves, only to find themselves resurrected in the same place?

What if no way out existed?

Fyodor advanced to the edge of the walk. Leaning over, he said, "Don't be afraid. We won't harm you. In fact, we want to help. We have rope. We'll let it down and pull you out of there."

"Are you out of your mind?" Cull whispered savagely. "They'll take our food away from us.

Maybe throw us into the river and leave us there. We can't take a chance. Let's beat it!"

There was no reply for a moment from the waders. They peered at them through the cracks between their fingers, as if their eyes were becoming somewhat adjusted to what must at first have been an intolerable glare. To them, the three must have been shadowy figures vaguely discerned in a painful blaze. But they must have seen those on the walk well enough for their purposes. One of the men reached out and grabbed an ex-ceptionally large piece of dung. He hurled it at Fyodor. The Slav, too surprised to dodge swiftly enough, was struck in the beard and chest.

Howling and hooting with laughter, the others imitated their companion. Cull and Phyllis ran out of range, but Fyodor was caught in the barrage.

Speechless, quivering, his face red in the torch-light, Fyodor stood with his hands around the rope, half-uncoiled from its position around his waist. Then, when the four in the river reached for other means of bombardment, he ran.

Cull expected him to start cursing, but Fyodor was praying softly, if somewhat incoherently. He seemed to be asking for mercy and deliverance for those who had attacked him after he had offered help.

"Poor devils, h.e.l.l!" Cull said. "They're not crazy. They like it here, they like what they have to eat! They didn't want you to rescue them. You were a danger to them.''

Fyodor's little blue eyes became wide, and he said, "You must be mistaken."

"Believe what you want to," Cull said. "But I know that type of pervert.''

"We must get them out, help them, even if they don't want us to," Fyodor said. He started to walk back toward them.

But he stopped as a shriek came from one of the group. Cull looked down into the river and could just make out, near the edge of the light cast by the torches, what was happening. The sewage-dwellers, excited by the intrusion, had forgotten their customary vigilance. Now, a monstrous head had appeared above the surface, followed by the top of a long limbless body that ended in porpoise-like fins. The yardlong tongue of the demon had lashed out and wrapped around the arm of one of the women. The hundreds of tiny teeth on the tongue were hooked into the flesh of the victim, and the woman was being pulled into the deeper regions of the water. (Evidently, the bottom was shallow near the oval island.) The others, screaming and flailing their arms in the water, were wading toward the island as swiftly as they were able.

The demon propelled himself backward into the deep, drawing the woman with him. He disap-peared, and her head went under after him, cut-ting off a scream in the middle. A few bubbles, and that was that.

Or so Cull thought. Some seconds later, she reappeared and began thrashing toward the island.

Blood flowed from wounds all over her body, lancing the black waters with red.

No use. The tongue twisted around one of her legs, back she went, and, in a short time, she was under again. The three waited for several minutes but saw no more of her.

"Now," Fyodor shouted, "will you let us help you?"

"Go to h.e.l.l!" shrieked one of the men.

Cull took Fyodor's hand and pulled him, still protesting, on down the walk. Afterward, when he had quit sobbing and was calm enough to listen, Cull talked to him.

"See. They enjoy their degradation."

"Why did she fight so hard for her life?" Fyodor said. "Wouldn't you think she'd be glad to die?"

"No, I wouldn't."

He looked searchingly at Cull, then said, "Why don't you think so? Is it because you're too much like them? Would you be the same if you stayed down here?"

Cull didn't answer.

A moment later, he brushed against the wall of the tunnel. And he jumped as if bitten. Or burned.

"The wall's hot," he said. "Well, not hot. Warm. Very warm."

From that point on, he kept the fingertips of his right hand on the wall. The warmth continued for about two hundred yards. Then, the temperature changed to normal. This lasted about two hundred yards. Suddenly, the wall became cold. Icy. With balloons of moisture clinging to the metal -- if it were metal.

For the next two hundred yards, the wall was cold. Then, neutral. Then, very warm again. After that, neutral. Then, cold. And so on.

"Parts of these walls," said Cull, "are the walls of hot or cold air shafts. They must be. It's only logical. You know that many of the statues in the city contain ventilation shafts. Hot air goes into some.

Cold air comes out of others. I always knew that and also knew why. This is an enclosed world with light furnished by a cold sun and heat provided by the radiation from billions of warm bodies. If there weren't some means of cooling the air, we'd have all been cooked to death long ago from the acc.u.mulated heat of our own bodies.

"Where does the cold air come from? Are there gigantic refrigeration devices buried deep below the surface? Or are other means used?"

"There's only one thing wrong with your theory," said Fyodor. "When this world expands, and the cities are dislodged from their places on the surface, the air shafts would snap off. However, this doesn't, obviously, happen. The hot-cold balance is maintained. So. . .?"

"Sharp. Good point. Since the ventilation isn't cut off, the shafts don't break. If they do, they're repaired or replaced. That doesn't seem likely when you consider the enormous labor and materials involved. Not to mention the time. So. . ."

"So?"