Chapter 6

The rat moved along the rusted steel rail that ran the length of the huge tunnel. To a human being, the tunnel would have seemed to be in utter darkness, but the little eyes of the rat saw the surroundings as faintly luminescent, glowing from the infra-red radiations given out by the internal warmth of the cement and steel. The main source of the radiations was from above, where the heat of the sun and the warmth from the energy sources in the buildings on the surface seeped through the roof of the tunnel. But here and there were even brighter spots of warmth, spots that moved about on glowing feet and sniffed blindly at the air with tiny glowing noses. Rats.

On and on moved the rat, its little pinkish feet pattering almost silently on the oxidized metal surface of the rails. Its sensitive ears picked up the movements and the squeals of other rats, but it paid them no heed. Several times it met other rats on the rail, but most of them sensed the alienness of _this_ rat and scuttled out of its way.

Once, it met a rat who did not give way. Hungry, perhaps, or perhaps merely yielding to the paranoid fury that was a normal component of the rattish mind, it squealed its defiance to the rat that was not a rat. It advanced, baring its rodent teeth in a yellow-daggered snarl of hate.

The rat that was not a rat became suddenly motionless, its sharp little nose pointed directly at the oncoming enemy. There came a noise, a tiny popping hiss, like that of a very small drop of water striking hot metal. From the left nostril of the not-rat, a tiny, glasslike needle snapped out at bullet speed. It struck the advancing rat in the center of the pink tongue that was visible in the open mouth. Then the not-rat scuttled backward faster than any real rat could have moved.

For a second the real rat hesitated, and it may be that the realization penetrated into its dim brain that rats did not fight this way. Then, as the tiny needle dissolved in its bloodstream, it closed its eyes and collapsed, rolling limply off the rail to the rotted wooden tie beneath.

The rat might come to before it was found and devoured by its fellows--or it might not. The not-rat moved on, not caring either way. The human intelligence that looked out from the eyes of the not-rat was only concerned with getting to the Nipe.

* * * * *

"That's how we found the Nipe," Colonel Mannheim said, "and that's how we keep tabs on him now. We have over seven hundred of these remote-control robots hidden in strategic spots throughout those tunnels now, and we can put more in whenever we want, but it took time to get everything set up this way. Now we can follow the Nipe wherever he goes, so long as he stays in those tunnels. If he went out through the one open-air exit up in the northern part of the island, we could have him followed by bird-robots. But"--he shrugged wryly--"I'm afraid the underwater problem still has us stumped. We can't get the carrier wave for the remote-control impulses to go very far underwater."

"How do you get your carrier wave underground to those tunnels?" Stanton asked. "And how do you keep the Nipe from picking up the radiation?"

The colonel grinned widely. "One of the boys dreamed up a real cute gimmick. Those old steel rails themselves act as antennas for the broadcaster, and the rat's tail is the pickup antenna. As long as the rat is crawling right on the rail, only a microscopic amount of power is needed for control, not enough for the Nipe to pick up with his instruments. Each rat carries its own battery for motive power, and there are old copper power cables down there that we can send direct current through to recharge the batteries. And, when we need them, the copper cables can be used as antennas. It took us quite a while to work the system out, but it's running smoothly now."

Stanton rubbed his head thoughtfully. _Damn these gaps in my memory!_ he thought. It was sometimes embarrassing to ask questions that any schoolboy should know the answers to.

"Aren't there ways of detecting objects underwater?" he asked after a moment.

"Yes," said the colonel, "several of them. But they all require beamed energy of some kind to be reflected from the object we want to look at, and we don't dare use anything like that." He sat down on one corner of the table, his bright blue eyes looking up at Stanton.

"That's been our big problem all along," he said seriously. "We have to keep the Nipe from knowing he's being watched. In the tunnels themselves, we've only used equipment that was already there, adding only what we absolutely had to--small things. A few strands of wire, a tiny relay, things that can be hidden in out-of-the-way places and can be made to look as though they were a part of the original old equipment. After all, he has his own alarm system in that maze of tunnels, and we have deliberately kept away from his detecting devices. He knows about the rats and ignores them. They're part of the environment. But we don't dare use anything that would tip him off to our knowledge of his whereabouts. One slip like that, and hundreds of human beings will have died in vain."

"And if he stays down there too long," Stanton said levelly, "millions more may die."

The colonel's face was grim as he looked directly into Stanton's eyes. "That's why you have to know your job down to the most minute detail when the time comes to act. The whole success of the plan will depend on you and you alone."

Stanton's eyes didn't avoid the colonel's. _That's not true_, he thought, _I'll be only one man on a team. And you know that, Colonel Mannheim. But you'd like to shove all the responsibility off onto someone else--someone stronger. You've finally met someone that you consider your superior in that way, and you want to unload. I wish I felt as confident as you do ... but I don't._

Aloud, he said: "Sure. Nothing to it. All I have to do is take into account everything that's known about the Nipe and make allowances for everything that's not known." Then he smiled. "Not," he added, "that I can think of any other way to go about it."

_THIRD INTERLUDE_

Mrs. Frobisher touched the control button that depolarized the window in the breakfast room, letting the morning sun stream in through the now transparent sheet of glass. Her attention was caught by something across the street, and she said, in a low voice, "Larry, come here."

Larry Frobisher looked up from his morning coffee. "What is it, hon?"

"The Stanton boys. Come look."

Frobisher sighed. "Who are the Stanton boys, and why should I come look?" But he got up and came over to the window.

"See--over there on the walkway toward the play area," his wife said.

"I see a boy pushing a wheeled contraption and three girls playing with a skip rope," Frobisher said. "Or do you mean that the Stanford boys are dressed up as girls?"

"_Stanton_," she corrected him. "They just moved into the apartment on the first floor."

"Who? The three girls?"

"No, silly! The two Stanton boys and their mother. One of them is in that 'wheeled contraption'. It's called a therapeutic chair."

"Oh? So the poor kid's been hurt. What's so interesting about that, aside from morbid curiosity?"

The boy pushing the chair went around a bend in the walkway, out of sight, and Frobisher went back to his coffee while his wife spoke.

"Their names are Mart and Bart," she said. "They're twins."

"I should think," Frobisher said, applying himself to his breakfast, "that the mother would get a self-powered chair for the boy instead of making the other boy push it."

"The poor boy can't control the chair, dear," said Mrs. Frobisher, still looking out the window after the vanished twins. "There's something wrong with his nervous system. I understand that he was exposed to some kind of radiation when he was only two years old. That's why the chair has to have all those funny instruments built into it. Even his heartbeat has to be controlled electronically."

"Shame," said Frobisher, spearing a bit of sausage. "Kind of rough on both of 'em, I'd guess."

"How do you mean, dear?"

"Well, I mean, like ... well, for instance, why are they going over to the play area? Play games, right? So the one that's well has got to push his brother over there. Can't just get out and go; has to take the brother along, too. Kind of a burden, see?"

Mrs. Frobisher turned away from the window. "Why, Larry! I'm surprised at you. Really! Don't you think the boy _should_ take care of his brother?"

"Oh, now, honey, I didn't mean that. It's hard on _both_ of 'em. The kid in the chair has to sit there and watch his brother play baseball or jai alai or whatever, while he can't do anything himself. Like I say, kind of rough on both of 'em."

"Well, yes, I suppose it must be. Want some more coffee?"

"Thanks, honey. And another slice of toast, hunh?"

_[10]_

Like some horrendous, watchful gargoyle, the Nipe crouched motionlessly on the shadowed roof of the low building. A short projection from the air-conditioning intake was wide enough to keep him from being seen from the air, and the darkness of the roof prevented anyone on the street from seeing the four violet eyes that kept a careful account of all that went on in the store across the way from his observation post.

The lights were still on inside the shop, shedding their glareless brightness through the transparent display windows to fall upon the street outside in large luminous pools. The Nipe knew exactly what each man remaining inside was doing, and approximately what each would be doing for the next few minutes, and he watched with the expectation that his prophecies would be fulfilled.

He had watched long and made a thorough study of this establishment, and tonight he expected to attain the goal for which he had worked so patiently.

This raid was important in two ways. There were pieces of equipment he had to get, and they were in that shop. On the other hand, this raid was, and would be, basically a diversionary tactic. Now that he had located his real target, it was time to create a diversion that would draw his enemy's attention away from his immediate surroundings. This would be a raid that Colonel Walther Mannheim could not ignore!

Two men came out the front door. They spoke to someone still inside. "So long." "See you tomorrow." Then they walked down the street together, conversing in low tones.

The Nipe waited.

Not until a fifth man stopped after he opened the door and flipped a switch on the inside did the Nipe make any motion. Then he flexed his four pairs of limbs in anticipation--but it wasn't quite time to act yet.

The interior lights of the shop went out. Then the man carefully locked the front door, setting the alarms within the shop. Then, serene in the belief that his establishment was thoroughly protected from burglars, he, too, went down the street.

The Nipe waited a few minutes longer before he left his observation post. All was normal, he decided. The time for action had come.

* * * * *

The Nipe moved cautiously along the alley toward the rear of the building that was his target. The night watchman had returned to his cubicle, as he always did after his preliminary inspection of the building's alarm system. He would not leave for some time yet, if he followed his habits. And the Nipe saw no reason why he should not.

Carefully he approached the rear door of the little optical shop.

_[11]_

The two massive objects floating in space looked very much like deeply pitted pieces of rock. The larger one, roughly pear-shaped and about a quarter of a mile in its greatest dimension, was actually that--a huge hunk of rock. The smaller--_much_ smaller--of the two was not what it appeared to be. It was a phony. Anyone who had been able to conduct a very close personal inspection of it would have recognized it for what it was--a camouflaged spaceboat.

The camouflaged spaceboat was on a near-collision course with reference to the larger mass, although their relative velocities were not great.

At precisely the right time, the smaller drifted by the larger, only a few hundred yards away. The weakness of the gravitational fields generated between the two caused only a slight change of orbit on the part of both bodies. Then they began to separate.

But, during the few seconds of their closest approach, a third body detached itself from the camouflaged spaceboat and shot rapidly across the intervening distance to land on the surface of the floating mountain.

The third body was a man in a spacesuit. As soon as he landed, he sat down, stock-still, and checked the instrument case he held in his hands.

No response. Thus far, then, he had succeeded.

He had had to pick his time precisely. The people who were already on this small planetoid could not use their detection equipment while the planetoid itself was within detection range of Beacon 971, only two hundred and eighty miles away. Not if they wanted to keep from being found. Radar pulses emanating from a presumably lifeless planetoid would be a dead giveaway.

Other than that, they were mathematically safe. Mathematically safe they would be if--and only if--they depended upon the laws of chance. No ship moving through the Asteroid Belt would dare to move at any decent velocity without using radar, so the people on this particular lump of planetary flotsam would be able to spot a ship's approach easily, long before their own weak detection system would register on the pickups of an approaching ship.

The power and range needed by a given detector depends on the relative velocity--the greater that velocity becomes, the more power, the greater range needed. At one mile per second, a ship needs a range of only thirty miles to spot an obstacle thirty seconds away; at ten miles per second, it needs a range of three hundred miles.

The man who called himself Stanley Martin had carefully plotted the orbit of this particular planetoid and had let his spaceboat coast in without using any detection equipment except the visual. It had been necessary, but very risky.

The Asteroid Belt, that magnificently useful collection of stone and metal lumps revolving about the sun between the orbits of Mars and Jupiter, is somewhat like the old-fashioned merry-go-round. If every orbit in the Belt were perfectly circular, the analogy would be more exact. If they were, then every rock in the Belt would follow every other in almost exactly the way every merry-go-round horse follows every other. (The gravitational attraction between the various bodies in the Belt can be neglected. It is much less, on the average, than the gravitational pull between any two horses on a carousel.) If every orbit of those millions upon millions of pieces of rock and metal were precisely circular, then they would constitute the grandest, biggest merry-go-round in the universe.

But those orbits are not circular. And even if they were, they would not remain so long. The great mass of Jupiter would soon pull them out of such perfect orbits and force them to travel about the sun in elliptical paths. And therein lies the trouble.

If their paths were exactly circular, then no two of that vast number of planetoids would ever collide. They would march about the sun in precise order, like the soldiers in a military parade, except that they would retain their spacing much longer than any group of soldiers could possibly manage to do.

But the orbits are elliptical. There is a chance that any two given bodies _might_ collide, although the chance is small. The one compensation is that if they do collide they won't strike each other very hard.

The detective was not worried about collision; he was worried about observation. Had the people here seen his boat? If so, had they recognized it in spite of the heavy camouflage? And, even if they only suspected, what would be their reaction?

He waited.

It takes nerve and patience to wait for thirteen solid hours without making any motion other than an occasional flexing of muscles, but he managed that long before the instrument case that he held waggled a meter needle at him. The one tension-relieving factor was the low gravity; the problem of sleeping on a bed of nails is caused by the likelihood of the sleeper accidentally throwing himself off the bed. The probability of puncture or discomfort from the points is almost negligible.

When the needle on the instrument panel flickered, he got to his feet and began moving. He was almost certain that he had not been detected.

Walking was out of the question. This was a silicate-alumina rock, not a nickel-iron one. The group of people that occupied it had deliberately chosen it that way, so that there would be no chance of its being picked out for slicing by one of the mining teams in the Asteroid Belt. Granted, the chance of any given metallic planetoid's being selected was very small--but they had not wanted to take even that chance.

Therefore, without any magnetic field to hold him down, and with only a very tiny gravitic field, the detective had to use different tactics.

It was more like mountain climbing than anything else, except that there was no danger of falling. He crawled over the surface in the same way that an Alpine climber might crawl up the side of a steep slope--seeking handholds and toeholds and using them to propel himself onward. The only difference was that he covered distance a great deal more rapidly than a mountain climber could.

When he reached the spot he wanted, he carefully concealed himself beneath a craggy overhang. It took a little searching to find exactly the right spot, but when he did, he settled himself into place in a small pit and began more elaborate preparations.

Self-hypnosis required nearly ten minutes. The first five or six minutes were taken up in relaxing from his exertions. Gravity notwithstanding, he had had to push his hundred and eighty pounds over a considerable distance. When he was completely relaxed and completely hypnotized, he reached up and cut down the valve that fed oxygen into his suit.

Then--of his own will--he went cataleptic.

A single note, sounded by the instruments in the case at his side, woke him instantly. He came fully awake, as he had commanded himself to do.

Immediately he turned up his oxygen intake, at the same time glancing at the clock dial in his helmet. He smiled. Nineteen days and seven hours. He had calculated it almost precisely.

He wasn't more than an hour off, which was really pretty good, all things considered.

He consulted his instruments again. The supply ship was ten minutes away. The smile stayed on his face as he prepared for further action.

The first two minutes were conscientiously spent in inhaling oxygen. Even under the best cataleptic conditions, the human body tended to slow down too much. He had to get himself prepared for violent movement.

Eight minutes left.

He climbed out of the little grotto where he had concealed himself and moved toward the spot where he knew the airlock to the caverns underneath the planetoid's surface was hidden.

Then again he concealed himself and waited, while he continued to breathe deeply of the highly oxygenated air in his suit. Five minutes before the ship landed, he swallowed eight ounces of the nutrient solution from the tank in the back of his helmet. The solution of amino acids, vitamins, and honey sugar also contained a small amount of stimulant of the dexedrine type and one percent ethanol.

He waited for another minute for the solution to take effect, then he unholstered his gun.

The supply ship wasn't a big one. He had known it wouldn't be. It was only a little larger than the one he had used to come out here. It dropped down to the surface of the small planetoid only ten meters from the hidden trapdoor that led to the airlock beneath the surface.

Suddenly he could hear voices in the earphones of his helmet.

_Lasser?_

_Yeah. It's me, Fritz. I got all the supplies and a nice package of good news._

The airlock trapdoor opened, and a spacesuited figure came out. _How about the deal?_

_That's the good news_, said the second suited figure as it came from the airlock of the grounded spaceboat. _Another five million._

The detective, hidden behind the nearby crag of rock, listened and watched for a minute or so while the two men began unloading cases of foodstuffs from the spaceboat. Then, satisfied that it was perfectly safe, he aimed his gun and shot twice in rapid succession.

The range was almost point-blank, and there was, of course, no need to take either gravity or air resistance into account.

The pellets of the shotgun-like charge that blasted out from the gun were small, needle-shaped, and massive. They were oriented point-forward by the magnetic field along the barrel of the weapon. Of the hundreds of charges fired, only a few penetrated the spacesuits of the targets, but those few were enough. The powerful drug in the needle-pointed head of each tiny crystal went directly into the bloodstream of each target.

Each man felt an itching sensation. He had less than two seconds to think about it before unconsciousness overtook him and he slumped nervelessly.

Gun in hand, the detective ran across the intervening space quickly, his body only a few degrees from the horizontal, and his toes paddling rapidly to propel him over the rough rock.

He braked himself to a halt and slapped air patches over the areas where his charges had struck the men's suits, sealing the tiny air leaks, and, at the same time, driving more of the tiny needles into their skins. They would be out for a long time.

Neither of them had yet fallen to the ground. That would take several minutes under this low gravity. He left them to drop and headed toward the open airlock.

This was what he had been waiting for all those nineteen days in cataleptic hypnosis. He couldn't have cut his way into the hideout from the outside; he had had to wait until it was opened, and that time had come only with the supply ship.

Once in the airlock, he touched the control stud that would close the outer door, pump air into the waiting room, and open the inner door. Here was his greatest point of danger--greater, even, than the danger of coming to the planetoid itself, or the danger of waiting nineteen days in a cataleptic trance for the coming of the supply ship. If the ones who remained within suspected anything--anything at all!--then his chances of coming out of this alive were practically nil.

But there was no reason why they should suspect. They should think that the man coming in was one of their own. The radio contact between the men outside had been limited to a few micromilliwatts of power--necessarily, since radio waves of very small wattage can be decoded at tremendous distances in open space. The men inside the planetoid certainly should not have been able to pick up any more than the beginning of the early conversation before it had been cut completely off by the intervening layers of solid rock.

The chamber he entered was a high-speed airlock. Unlike the soundless discharge of his special gun in the outer airlessness, the blast of air that came into the waiting chamber was like a hurricane in noise and force. The room filled with air in a very few seconds.

The detective held on to the handholds tightly while the brief but violent winds buffeted him. He turned as the inner door opened.

His eyes took in the picture in a fraction of a second. In an even smaller fraction, his mind assimilated the picture.

The woman was dark-haired, dark-eyed, and muscular. Her mouth was wide and thick-lipped beneath a large nose.

The man was leaner and lighter, bony-faced, and beady-eyed.

The woman said: "Fritz, what--?"

And then he shot them both with gun number two.