The big tunnel inside the cliff was long and black, and the air was stale and thick with the stench of rodents. Stanton stood still for a minute, stretching his muscles. Crawling through that cramped little opening had not been easy. He looked around him, trying to probe the luminescent gloom that the goggles he wore brought to his eyes.

The tunnel stretched out before him—on and on. Around him was the smell of viciousness and death. Ahead ...

It goes on to infinity, Stanton thought, ending at last at zero.

The rat paused and looked back, waiting for him to follow.

"Okay," Stanton muttered. "Let's go."

The rat led him down the long tunnel, deep into the cliffside, until at last they came to a stairway that led downward into the long tunnels where the trains had once run. They came to the platform where passengers had once waited for those trains. Four feet below the edge of the platform were the rusted tracks that had once borne those trains.

He lowered himself over the edge to stand on the rail.

"Barbell," said a voice in his ear, "Barhop here. Do you read?"

It was the barest whisper, picked up by the antennas in his shoes from the steel rail that ran along the floor of the dark tunnel.

"Read you, Barhop."

"Move out, then. You've got a long stroll to go."

Stanton started walking, keeping his feet near the rail, in case Greer wanted to call again. As he walked, he could feel the slight motion of the skin-tight woven suit that he wore rubbing gently against his skin.

And he could hear the scratching patter of the rats.

Mostly they stayed away from him, avoiding the strange being that had invaded their underground realm, but he could see them hiding in corners and scurrying along the sides of the tunnels, going about their unfathomable rodent business.

Around him, six rat-like remote-control robots moved with him, shifting their pattern constantly as they patrolled his moving figure.

Far ahead, he knew, other rat robots were stationed, watching and waiting, ready to deactivate the Nipe's detection devices at just the right moment. Behind him, another horde moved forward to turn the devices on again.

It had, he knew, taken the technicians a long time to learn how to shut off those detectors without giving the alarm to the Nipe's instruments.

There were nearly a hundred men in on the operation, controlling the robot rats or watching the hidden cameras that spied upon the Nipe. Nearly a hundred. And every single one of them was safe.

They were all outside the tunnel and far away. They were with Stanton only by proxy. They could not die here in this stinking hole, no matter what happened. But Stanton could.

There was no help for it, no other way it could be done. Stanton had to go in person. A full-sized robot proxy might be stronger, although not faster unless Stanton was at the controls, than the Nipe. But the Nipe would be able to tell that the thing was a robot, and he would simply destroy it with one of his weapons. A remote-control robot could never get close enough to the Nipe to do any good.

"We do not know positively," Dr. Yoritomo had said, "whether he would recognize it as a robot or not, but his instruments would show the metal easily enough, and his eyes would be able to tell him that the machine was not covered with human skin. The rats are small enough so that they can be made mostly of plastic, and they are covered with real rat hides. In addition, our friend, the Nipe, is used to seeing them around. But a human-sized robot? Ah, no. Never."

So Stanton had to go in person, walking southward along the tracks, through the miles of blackness that led to the nest of the Nipe.

Overhead was Government City.

He had looked out upon those streets only the night before, and he knew that only a short distance away there was an entirely different world.

Somewhere up there, his brother was waiting, after having run the gamut of publicity. He was a celebrity. "Stanley Martin, the greatest detective in the Solar System," they'd called him. Fine stuff, that. Stanton wondered what the asteroids were like. What would it be like to live out in space, where a man still had plenty of space to move around in and could fashion his life to suit himself? Maybe there would be a place in the asteroids for a hopped-up superman.

Or maybe there would only be a place here, beneath the streets of Government City, for a dead superman.

Not if I can help it, Stanton thought with a grim smile.

The walking seemed to take forever in one way, but, in another way, Stanton didn't mind it. He had a lot to think over. Seeing his brother's image on the TV had been unnerving yesterday, but today he felt as though everything had been all right all along.

His memory was still a long way from being complete, and it probably always would be, he thought. He could still scarcely recall any real memories of a boy named Martin Stanton, but—and he smiled a little at the thought—he knew more about him than his brother did, even so.

It made very little difference now. That Martin Stanton was gone. In effect, he had been demolished—what little there had been of him—and a new structure had been built on the old foundation.

And yet, it was highly probable that the new structure was very like that that would have developed naturally if the accident so early in Martin Stanton's life had never occurred.

Stanton kept walking. There was a timeless feeling about his march through the depths of the ground, as though every step through the blackness was exactly like every other step, and it was only the same step over and over again.

He skirted a pile of rubble on his right. There had been a station here, once; the street above had caved in and filled it with brick, concrete, cobblestones, and steel scrap, and then it had been sealed over when Government City was built.

A part of one wall was still unbroken, though. A sign built of tile said 125TH STREET, he knew, although it was hard to make it out in the dim glow. He kept on walking, ignoring the rats that scampered over the rubble.

A mile or so farther on, he whispered: "Barbell to Barhop. How's everything going?"

"Barhop to Barbell," came the answer. "No sign of any activity from Target. So far, none of the alarms have been triggered."

"What's he doing?" Stanton whispered. It seemed only right to keep his voice low, although he was fairly certain that his voice would not carry to the Nipe, even through these echoing tunnels. He was still miles away.

"He's still sitting motionless," said Captain Greer. "Thinking, I suppose. Or sleeping. It's hard to tell."

"All right. Let me know if he starts moving, will you?"

"Will do."

Poor unsuspecting beastie, Stanton thought. Ten long years of hard work, of feeling secure in his little nest, and within a very short time he's going to get the shock of his life.

Or maybe not. There was no way of knowing what kind of shocks the Nipe had taken in the course of his life, Stanton thought. There was no way of knowing whether the Nipe was even capable of feeling anything like shock, as a matter of fact.

It was odd, he thought, that he should feel a strong kinship toward both the Nipe and his brother in such similar ways. He had never met the Nipe, and his brother was only a dim picture in his old memories, but they were both very well known to him. Certainly they were better known to him than he was to them.

And yet, seeing his brother's face on the TV screen, hearing his voice, watching the way he moved about, watching the changing expressions on his face, had been a tremendously moving experience. Not until that moment, he thought, had he really known himself.

Meeting him face to face would be much easier now, but it would still be a scene highly charged with emotional tension.

His foot kicked something that rattled and rolled away from him. He stopped, freezing in his tracks, looking downward, trying to pierce the dully glowing gloom. The thing he had kicked was a human skull.

He relaxed and began walking again.

There were plenty of human bones down here. Mannheim had told him that the tunnels had been used as air-raid shelters when the sun bomb had hit the island during the Holocaust. Men, women, and children by the thousands had crowded underground after the warning had come—and they had died by the thousands when the bright, hot, deadly gases had roared down the ventilators and stairwells.

There were even caches of canned goods down here, some of them still perfectly sealed after all this time. The hordes of rats, wiser than they knew, had chewed at them, exposing the steel beneath the thin tin plate. And, after a while, oxidation would weaken the can to the point where some lucky rat could gnaw through the rusty spot and find himself a meal. Then he would move the empty can aside and begin gnawing at the next in line. He couldn't get through the steel, but he would scratch the tin off, and the cycle would begin again. Later, another rat would find that can weak enough to bite through. It kept the rats fed almost as well as an automatic machine might have.

The tunnel before him was an endless monochromatic world that was both artificial and natural. Here was a neatly squared-off mosaic of ceramic tile that was obviously man-made; over there, on a little hillock of earth, squatted a colony of fat mushrooms. In several places he had to skirt little pools of dark, stagnant water; twice he had to climb over long heaps of crumbling rust that had once been trains of subway cars.

He kept moving—one man, alone, walking through the dark toward a superhuman monster that had terrorized Earth for a decade.

A drug that would knock out the Nipe would have been very useful, but to synthesize such a drug would have required a greater knowledge of the biochemical processes of the Nipe than any human scientist had. The same applied to anesthetic gases, or electric shock, or supersonics. There was no way of determining how much would be required to knock him out or how much would be required to kill. There were no easy answers.

The only answer was a man called Stanton.

Stanton hummed the song in his mind. It seemed that he had been walking forever through the Kingdom of Hades, while around him twittered the ghosts of the dead.

Poor shades, he thought, entertaining the fancy for a brief moment, will I be one of you in a short while?

There was no answer, though the squeaking continued. The sound of his feet and the snarling chirping of the rats were the only sounds in the world.

"Barhop to Barbell," said a voice suddenly, sounding very loud in his ear, "this is where you have to make your change to the other tunnel."

"Barbell to Barhop. I know. I've been watching the markers."

"Just precaution, Barbell," Captain Greer said. "How do you feel?"

"I'd like to rest for a few minutes, frankly," Stanton said.

"Feeling tired?" There was just the barest tinge of alarm in the captain's voice.

"No," Stanton said. "I just want to sit down and rest my feet for a few minutes."

There was a pause. Then the captain's voice came again. "Okay, go ahead and relax, Barbell. Take ten. But be ready to move fast if I yell. These alarm systems are tricky things to hold. And don't start moving again without letting me know."

"Right."

Stanton lifted himself out of the trench in which the tunnel ran and sat on the edge of the boarding platform. It wasn't far now. There was only one more of the old entranceways between himself and the Nipe. This particular one was a transfer point, where two different parts of the tunnel network met and it was possible to transfer from one to another. It required going up a couple of flights of stairs to the next higher level, and changing to another tunnel going southward.

There were other ways. This tunnel, the one he had been following for so long, branched a little farther south. If he took one branch, he would end up to the east of the Nipe; the other would bring him to a point on the west. From either, he would have to travel laterally through another set of tunnels, but neither route offered anything that this one didn't have, and the most direct route would be best.

"Barbell to Barhop," he whispered, "I'm ready to go."

"It's only been five minutes."

"I know. But I rest pretty fast, too. Let's move out."

There were a few seconds of silence, then Captain Greer said: "All set, Barbell. Move out."

Stanton got to his feet and walked toward the stairway that led up to the next level. Minutes later, he was in another tunnel exactly similar to the first one, walking southward again.

But now he was more careful. He watched the ground carefully, making sure that he didn't step on anything that would snap or rattle. The Nipe was still quite a distance away—three-quarters of a mile, or so—but taking the chance that the beast couldn't hear him might be deadly dangerous. The robot rat that he was following led him along a path that had been unobtrusively cleared of rubble by the robot rats over a period of months, but the robots weren't the only rats in the place. He kept his eyes on the path.

A while later, the voice in his ear said: "A hundred yards to go, Barbell."

"I know," Stanton whispered. "He hasn't moved?"

"No. I'll yell if he does. You don't need to talk any more. His ears might pick up even that whisper."

He hasn't moved, Stanton thought. Not for all this time. Not since I came down into his private domain. All this time, he has been sitting motionless—waiting. Wouldn't it be funny if he were dead? If his heart had stopped, or something. Wouldn't that be absolutely hilarious? Wouldn't that be a big joke on everybody? Especially me.

Ahead was the large area that had been one of the major junction points of the tunnel network. This was the area that the Nipe had taken over to build his home-away-from-home. Here were his workshops, his laboratories, his storerooms.

And somewhere here was the Nipe.

He came out of the tunnel into another passenger-loading area. Just to his left was another short stairway that led up to a slightly higher level. He moved slowly and quietly. He didn't want to fight down here on the tracks, and he didn't want to be caught just yet.

Cautiously he lifted himself to the platform where long-gone passengers had once waited for long-gone trains.

The quality of the illumination at the head of the stairs was different from that which he had been used to for the past three hours. He lifted off the infra-red goggles. Enough light spilled over from the Nipe's lair to give him illumination to see by. Silently, he put the goggles on the floor of the platform. He wouldn't need them again.

Then, step by step, he walked up the concrete stairway.

At the head of the stairs, he paused to get his bearings.

The illumination was not bright, but it was enough to—

"Barbell! He's heard you! Watch it!"

But Stanton had already heard the movement of the Nipe. He jerked off the communicator and threw it down the stairs behind him. He wanted no encumbrances now!

He ran quickly out into the center of the big underground room, away from the open stairwell.

And then, as fast as any express train that had ever moved through these subterranean ways, the Nipe came around a corner thirty feet away, his four violet eyes gleaming, his limbs rippling beneath his centipede-like body.

From fifteen feet away, he launched himself through the air, his outstretched hands ready to kill.

But Stanton's marvelous neuromuscular system was already in action.

At this stage of the game, it would be utter suicide to let the Nipe get in close. Stanton couldn't fend off eight grasping hands with his own two. He leaped to one side, and the Nipe got his first surprise in ten years when Stanton's fist slammed against the side of his snouted head, knocking him in the direction opposite that in which Stanton had moved.

The Nipe landed, turned, and charged back toward the man. This time he reared up, using his two rearmost pairs of limbs for locomotion, while the two forward pairs were held out, ready to kill.

He got surprise number two when Stanton's fist landed on the tip of his rather sensitive snout, rocking his head back. His own hands met nothing but air, and by the time he had recovered from the blow, Stanton was well back, out of the way.

He's so small! Stanton thought wonderingly. Even when he reared up, the Nipe's head was only three feet above the concrete floor.

The Nipe came in again—more cautiously this time.

Stanton punched again with a straight right. The Nipe moved his head aside, and Stanton's knuckles merely grazed the side of the alien's head, just below the lower right eye.

At the same time, one of the Nipe's hands swung in in a chopping right hook that took Stanton just below the ribs. Stanton leaped back with a gasp of pain.

The Nipe didn't use fists. He used his open hand, fingers together, like a judo fighter.

The Nipe came forward, and, as Stanton danced back, the Nipe made a grab for his ankle, almost catching it. There were too many hands to watch!

Stanton had two advantages: weight and reach. His arms were almost half again as long as the Nipe's.

Against that, the Nipe had all those hands; and with his low center of gravity and four-footed stance, it would be hard to knock him down. On the other hand, if Stanton lost his footing, the fight would be over fast.

Stanton lunged suddenly forward and planted a left in the Nipe's right upper eye, then followed it with a right uppercut to the Nipe's jaw as his head snapped back. The Nipe's four hands cut inward from the sides like sword blades, but they found no target.

Backing away, Stanton realized he had another advantage. The Nipe couldn't throw a straight jab! His shoulders—if that's what they should be called—were narrow and the upper arm bones weren't articulated properly for such a blow. The alien could throw a mean hook, but he had to get in close to deliver it.

On the other side of the coin was the fact that the Nipe knew plenty about human anatomy—from the bones out. Stanton's knowledge of Nipe anatomy was almost totally superficial.

He wished he knew if and where the Nipe had a solar plexus. He would like to punch something soft for a change.

Instead, he tried for another eye. He danced in, jabbed, and danced out. The Nipe had ducked again, taking the blow on the side of his head.

Then the Nipe came in low, at an angle, trying for the groin. For his troubles, he got a knee in the jaw that staggered him badly. One grasping hand clutched at Stanton's right thigh and grabbed hard. Stanton swung his fist down like a pendulum and knocked the arm aside.

But there was a slight limp in his movements as he back-pedaled away from the Nipe. That full-handed pinch had hurt like the very devil!

Stanton was angry now, with the hot, controlled anger of a fighting man. He stepped in quickly and slammed two fast hard jabs into the point of the Nipe's snout, jarring the monster backward. And this time it was the Nipe who scuttled back out of the way.

Stanton moved in fast to press his advantage and landed a beaut on the Nipe's lower left eye. Then he tried a body blow. It wasn't too successful. The alien had an endoskeleton, but he also had a tough hide that was somewhat like thick, leathery chitin.

Stanton pulled back, getting out of the way of the Nipe's open-handed judo cuts.

His fists were beginning to hurt, and his leg was paining him badly where the Nipe had clamped onto it. And his ribs were throbbing where the Nipe had landed that single blow.

And then he realized that, so far, the Nipe had only landed that one blow!

One punch and one pinch, Stanton thought with a touch of awe. The only other damage he's inflicted has been to my knuckles!

The Nipe charged in again, then he leaped suddenly and clawed for Stanton's face with his first pair of hands. The second and third pairs chopped in toward the man's body. The last pair propelled him off the floor.

Stanton stepped back and drove in a long, hard right, hitting him just below the jaw, where his throat would have been if he had been human.

The Nipe arced backward in a half somersault and landed flat on his back.

Stanton backed up a little more, waiting, while the Nipe wiggled feebly for a moment. The Marquis of Queensberry should have lived to see this, he thought.

The Nipe rolled over and crouched on all eight limbs. His violet eyes watched Stanton, but the man could read no expression on that inhuman face.

"You did not kill."

For a moment, Stanton found it hard to believe that the hissing, guttural voice had come from the crouching monster.

"You did not even try to kill."

"I have no wish to kill you," Stanton said evenly.

"I can see that. Do you ... Are you ..." He stopped, as if baffled. "There are not the proper words. Do you follow the Customs?"

Stanton felt a surge of triumph. This was what George Yoritomo had guessed might happen!

"If I must kill you," Stanton said carefully, "I, myself, will do the honors. You will not go uneaten."

The Nipe sagged a little, relaxing all over. "I had hoped it was so. It was the only thinkable thing. I saw you on the television, and it was only thinkable that you came for me."

Stanton sighed inwardly. That part of Colonel Mannheim's strategy had worked, too. The Nipe had seen all the publicity releases that had been so carefully tailored for him.

"I knew you were out on the asteroids," the Nipe went on. "But I had decided that you had come to kill. Since you did not, what are your thoughts, Stanley Martin?"

"That we should help each other," Stanton said.

It was as simple as that.

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