Part 2

His voice hardened. "They don't kill for the pure love of evil. They're intelligent beings, doing what they believe _has_ to be done. I think they're wrong, and I can't understand them--though I wish I could. I consider poisoning bedbugs a wise move, though no intelligent bedbug would agree with me. This expedition of theirs would be a major job for any trace, and they're going at it just as we would--if we had to exterminate the boll weevil.

"Emotions haven't a thing to do with it. We're in a battle for raw survival, and we haven't the time to indulge our animal emotions. It's a scientific problem that has to be solved for our lives--like a plague."

Norden added another intangible to the puzzle--either Miles was setting a trap for him, or it was hard to understand how he'd gotten the five stars on his insignia. An enemy was an enemy! He decided on silence as the best course, and was glad when the others began to leave. He watched them moving out, shocked again at the pretense that was going on. Did they really think war to the death was a game?

He started to follow, then hesitated, swayed by a sudden impulse. Surely it could do no harm. He located one of the waiters and asked for a package of food to take to Pat. To his relief, the man showed no surprise, and he soon had a bag in his hand.

Pat was still sitting at the machine. She took the food with a pleased smile that told him he'd done the right thing. "Why so glum?" she asked.

"Frankly, I'm puzzled," he told her. On a sudden impulse, he mentioned the lecture and how it had disturbed him.

"Dad!" She smiled, then laughed outright. "He always talks like that to a new man. Bill, did you ever see a little boy fighting a bigger one, wading in, crying, whimpering, but so mad he couldn't stop--couldn't even see where he was hitting? That's hate-fighting. And it's senseless, because the other side may be just as right. Professional fighters don't really hate--they simply do everything they can to win, coldly and scientifically."

She touched his arm. "Bill, be sensible. You act as if we _couldn't_ win."

"What makes you think we can?"

"The computer thinks so. I tried it. We'll win because we know how to be efficient. We'll experiment a bit, because we don't have a set pattern--because we've kept individuality. The Aliens act like a preset machine. Like a crew killing pests.

"Start at the outside of a circle and exterminate inwards! Nonsense! They should have hit Earth at once, even if they had to retrace their steps a few times. But they aren't trying to find out whether we act like the enemy they planned on. No--what's the proper way is the proper way. A lot of our nations attempted that once--and look where they are now."

He shook his head, not believing her, but it left him uncertain and disturbed. The fact was that the enemy was closing the net--closing it so fast he'd be a dead man in two weeks, if he couldn't find the solution. As to hatred....

He shook his head, and went into his office. There were copies of his own published works there, as well as magazines he hadn't yet seen. He dropped down to fill in the flaws his memory had developed.

Paraphysics was tricky stuff. For a long time men had known no other spectrum but the electromagnetic, running from heat up through cosmic rays. When atomic particles moved from one energy level to another, they produced quanta of energy in that spectrum, which was limited to the speed of light.

The kinetogravitic spectrum began with gravity and moved up through nuclear binding force toward some unknown band. Apparently it was the product of the behavior of some sub-particle finer than any known, and its speed of propagation was practically infinite. Other spectra were being considered, but no order or logic had fitted yet.

He found an article by a Japanese scientist that suggested there might be a spectrum related to the behavior of atoms in the molecule--with crystals in some cases acting on one level due to the electron drift, and on another due to atomic strains within the molecule. Colloids, polymers and even the encephalograph waves were dragged in, but the mathematics seemed sound enough.

Norden caught his breath, and began digging into the equation. The third manipulation suggested that magnetism might somehow be involved, and that would mean....

He couldn't dig the idea out. Just when it seemed about to open before him, his mind shied away and drifted off to other things. He was still working on it when Pat came in, and dropped a sheaf of papers on the table. Strips of tape had been pasted together to form a crude book.

"The whole thing," she reported. "But most of it's nonsense. There's a page or two about some secret asteroid where the survivors of the fifth planet are waiting for men to mature before bringing the Great Millenium--or pages where Hardwick worked on the numerology of your name before he discovered your middle name had no H in it--or little notes to himself about buying a gross of Martian sand lizards. I had the machine go through it, strike out all meaningless matter, and come up with this."

It was a clip of five sheets. Norden skimmed through them, and groaned. The shield he had tested for Hardwick had been made of genuine mummy cloth, ground mandrake and a glue filled with bat blood.

"Yet you _did_ live," Pat pointed out. "And he was right about their being able to detect life. We sent out sterile neoprene balloons loaded with live rabbits, and others with dead rabbits. Every balloon with the live rabbits was blasted--and none with the dead animals. We could use the same test to find out whether any one of those things worked--or any combination of them."

"We'll have to," he decided. "And then it may have been the closet instead of the shield--or an accident to their detector that saved me. Pat, have they got some kind of library here?"

It was already quitting time, but she went with him while he persuaded the library attendant to let him in, before the next shift came on. Mummy cloth, it seemed, might become infused with a number of aromatic preservatives, products from the mummy, and such.

It was ridiculous--but hardly more ridiculous than using the byproducts of mold to cure disease must have seemed. Anything dealing with life was slightly implausible. And when he phoned in the order for the materials to Miles, there were no questions.

"Thanks, Pat," he told her after she'd shown him where his sleeping quarters were located.

She shrugged. "Why? If we _don't_ find the answer, I'll be as dead as you in a few weeks."

He shuddered, and then put it out of his mind. Worrying about death wasn't decent, somehow. He found his bunk, stretched out with his hands behind his neck, and tried to review the serious events of the day, without the problem of hatred, over-efficiency, or Pat and her father. He saved those to worry about in his mind after he rolled over on his side, and gave up all ideas of sleeping.

Then abruptly there was a yell from down the hall, and lights snapped on. Norden sprang out with the others, to see the outer lock click shut. In the glare of the overhead lights, he could see a figure running desperately for the edge of a further Quonset--running in the airlessness of the exposed surface without a spacesuit!

More lights snapped on, and a guard in a suit came around the corner, throwing up a rifle. There was a tiny spurt of flame from the weapon, and the running man pitched forward. The guard started toward him just as a few men began to dart out of the huts in hastily-donned spacesuits.

A greenish-yellow effulgence bloomed shockingly where the runner had fallen, and the floor shook under Norden. The guard was thrown backwards, and the others stumbled. When the explosion was over there was no sign of the man who had run.

"Alien!" somebody muttered. "A damned Alien! They always blow up like that before you can get near them! I've seen it out in space!"

And Norden remembered the bomb that had wrecked the dome on the asteroid--a bomb that had flared up with the same greenish-yellow color.

Guards came up to drive the men back to their huts, but Norden seemed to have high enough rating to stay for a while. He learned that one of the workers was missing, and that it had been his badge which the Alien had worn to enter the sleeping sections. Either the Alien had killed and destroyed the worker for his clothing or else he had been the worker!

And he had been discovered forcing the lock on the sub-section of the hut where Norden had been sleeping!

III

The invasion of the base by the Alien had shocked them all, and few people had slept during the night. On his way to breakfast, Norden could feel the attention that was riveted on him. To the others, he was probably one of the most likely targets for whatever attack had been intended. He'd wondered about it himself, sick with a feeling of close disaster; but he could find no logical basis for the fear.

Miles waited until they had finished with their food, his own face a study in grim anxiety. Then he stood up, and faced them. "No work this morning," he announced. "There's going to be a fluoroscopic test of every person on the base!"

Norden felt a wrench at his mind that left his thoughts spinning. He caught himself, just as he heard a gasp from Armsworth, a few places down. But Miles went on as if nothing had happened.

"The guards have already been checked. They'll lead us all down to the explosive test chamber. We'll go in, one at a time, and stand on a marked square. The fluoroscope results will show on a television screen visible to all of us. If you pass, you'll go across the chamber to the cleared rooms beyond.

"Any man resisting or proven non-human will be shot at once. The Alien last night _looked_ human, but he didn't breathe oxygen, so his internal structure must be different. However, if anyone wants to declare that he's an Alien, he'll be treated as a prisoner of war instead of a spy."

Nobody made such a declaration, and Miles nodded to the guards who had filed in, while fear-ridden faces were still staring at their neighbors. Norden wondered how long a confessed Alien would last before the men tore him to bits. Discounting hate was fine at long range--but not when the danger was at your elbow.

Miles and Pat went into the chamber first, with the expected result--human skeletons and shadowy organs showing up on the screen. Norden stared in fascination, while fear built up tensions inside him.

Armsworth passed in and found his position, with a face that was somehow both taut and frozen. The guards took a look at the screen and waved him on. He half staggered to the exit, his features distorted with an emotion that was unreadable.

Norden tried to fight down his own panic. Surely it would be madness to doubt the outcome. But a doubt began to throb in his mind. He could remember so little. He'd thought the Aliens had never found him. But if they had actually captured him, tampered with his mind, and turned him back again, would he know it? Suppose he was an Alien--one given a spurious, hypnotic belief he was Norden until the right signal to become himself again....

It was ridiculous, absurd! But the speculations ran on in his tormented mind. He didn't belong here. Men apparently took it for granted that a confessed spy could keep his life--and Norden took it equally for granted that death was the only answer. He didn't think like the rest of them. There had been that week on the asteroid. His memories were spotty....

"Dr. William Norden!" the speaker announced.

He shuddered convulsively. Then he caught himself, and forced his reluctant legs to move. The door shut behind him, and ahead lay the white square on which he was to stand. He approached the spot automatically, bracing himself to face straight ahead toward the fluoroscopic screen.

_Now!_ It was almost a physical voice in his head. And his mind seemed to shift, to shout something down. _Not yet! Look!_

"Okay, Dr. Norden," the speaker said. His eyes flicked to the screen where a human skeleton showed dimly.

Crazy, he told himself. Hagridden with fears no sane human mind could have endured and retained its sanity. No wonder the psychologists had been uncertain about him. Unbalanced--but human!

Pat smiled weakly at him as he entered the room beyond, to join the ranks of the elect. Then they watched as their group passed successfully, to give place to a number of rocket men from the freight gang.

The sixth rocket man came through the door boldly enough--and suddenly leaped toward the side of the chamber where another door was. His hands were jolting at the locked barrier when the rifles sounded. A violent blast of greenish-yellow explosion rocked the chamber and shook the floors beyond. When it cleared, the Alien was dust and vapor, with nothing that could be studied for evidence.

Two workers who had been standing in line in a building beyond broke through the seal together, without waiting their turn, and headed with desperate haste for the shelter of a nearby barracks. A rifle bullet tore into one, and both exploded instantly.

By the time the rest had been proved safe in a testing ordeal as grim as death, it was the hour for lunch--a shocked, silent interlude at first. Then one of the men caught sight of a neighbor busily shaking his fork, and glancing sideways to emphasize some point. A tiny gadget appeared, and was concealed quickly under the steak on the man's plate. Ten seconds later, when the man cut into the meat, there was a cowlike bellow and the meat leaped six inches up, and two feet sideways. There was a shout of laughter that grew into a roar, and everything was suddenly normal again.

Norden shook his head. The incident appeared grotesque to him. Fluoroscope or not, something was wrong with him. He couldn't have been so different from other men before the ordeal on Hardwick's asteroid. That ruined steak had cost a small fortune to transport from Earth, and the man would lose valuable time while waiting for another to be cooked. And yet, Norden could see that somehow it had been effective therapy, had relieved an almost intolerable tension.

They spent the afternoon sending out the test "balloon" rockets with the various elements of Hardwick's screen. On the way back to the barracks, Norden noticed there were now six guards stationed about the laboratory, two of whom instantly fell into step behind him. He had been shifted to the dormitory over the Headquarters building, where he would be in the least danger--and also have the least freedom from observation!

But he forgot it the next day as the results of the tests came in. The shields had been completely ineffective. Dead rabbits still were unmolested, but live ones had been picked off in everything they had sent out.

Miles accepted the result with a despairing shrug, but Pat was hit hard by it. None of the other research teams seemed to be getting anywhere. There was no way to detect Aliens, and no way to screen humans.

On the fourth day, when the last possible variation of Hardwick's formula had proved useless, and the Aliens had moved their lines up to fifty million miles from Earth's orbit, Pat was down early, re-checking the translation the computer had made. Norden came in, saw the results, and swore.

For three hours, he pored over the Japanese scientist's mathematics--and as before, he found his mind reaching for something, only to begin some useless side speculation that threw him off. It was as if he had a censor in his mind telling him he could go no further. He considered the grim prospect of ten days or more of life for himself, and the men here, until the noonday signal sounded.

Somebody had put a new plastic glue on the handle of his knife and fork, and it was fifteen minutes before he could locate a solvent that removed it. Pat laughed at his plight along with the others. He checked his anger, swallowed it--and suddenly realized that in a strange way, the practical jest played on him was a mark of acceptance.

He went back to the laboratory trying to think of something ingenious enough to enable him to live up to their queer code. An idea that had nagged him tantalizingly, just below consciousness, nibbled again at his mind, but he let it go. If he could fit a protogravity generator under a plate....

And abruptly, he was digging for the complete set of Hardwick's notes, and scanning the nonsense that the computer had declared meaningless. He picked up the telephone and called the library. "Give me what you've got on Martian sand lizards!"

Most of it was useless. They were typical low-grade Martian life, tiny things covered with fur, but vaguely lizard-like. Then the significant part came. "The females demonstrate a remarkable ability to locate the rare males at extreme distances. Janiekowski found that a female with all sense organs removed could locate a male at a distance of five kilometers, even when the male was enclosed in an airtight box of laminated copper and soundboard. No satisfactory explanation is known."

It _had_ to be some form of telepathy or sensitivity to the life forces of the male lizards! He went over the work done with the creatures a dozen times, and could find no other explanation. And suddenly his mind was milling about, trying to slide away from it again.

"Taboo!" he muttered. "_Damn_ the taboo!" It was too late for a taboo to interfere now, whatever the reasons behind it. And fortified by his growing certainty that something had been done to him, it only served to confirm the fact that he was on the right track at last.

Pat listened to his summary of what he'd found, and nodded hopeful agreement. "A quick test! It's what we need, all right. We still may not find the insulator for the shield, but we can run tests fast enough to have a chance. Metals first, then the other broad classifications, until something vital turns up. Bill, I guess this makes me, and the computer look pretty silly. And after all the yelling I've done about flexibility being needed, too. I hope some zoo or laboratory on Earth has a collection of the little beasts."

It turned out that Harvard was well stocked as a result of a research plan to rework Janiekowski's experiments. In less than five hours, twelve females and two rare males were lying in front of Norden. They looked like small lizards covered with chinchilla hair, and possessing eight legs apiece. The females, with scant modesty, were trying busily to break down the wall that kept them from the males.

Pat had already installed three television pickups and cages at various distant points, doing the work herself to insure secrecy, and picking places most difficult to break into. Now she came back to move the females to their new homes, where they immediately began trying to crawl toward the torpid males, as shown by the television screens. The walls of their cages were equipped with pressure-measuring devices to test the strength of their efforts.

The mummy cloth drew a complete blank, as did the bat's blood. But the ground mandrake set the males to pawing at their cake with their triple tongues out, trying to reach it, while the distant females went berserk.

Pat took the stuff away, snorting at them. "They'll die of frustration in another minute. To them an active male seems to be a combination billionaire, video star, and accomplished Cassanova in the art of love. I guess I know how they feel."

He was getting better at reading her glances, and he frowned as her eyes rested upon him. He liked Pat, but sometimes she--

She laughed. "Forget it, Bill. I was only ribbing you. You have about as much romantic appeal to me as my grandfather."

It was ten minutes later before he realized what a typical masculine _human_ reaction to such a remark would have been. He frowned, while his mind chilled at the implications. How could he doubt any longer that the Aliens had caught him and done something to him--something drastic? He wasn't quite human, despite what the bones of his body had seemed to confirm.

And that could only mean that Hardwick's shield had never worked. He stopped short, and then reconsidered. The difficulty he had forcing his mind to think about tests for the lizards still spelled a taboo in his mind--and that indicated there might be a shield. It left him exactly where he was, except for the problem of what the Aliens wanted. If he could solve that, and defeat it....

Nothing they tried gave any positive result, though Pat thought that the variation in the female activity had been slightly more than normal when they'd tried the potassium salt solution around the males. They gave up late, and Norden went back to his bunk, and to the familiar pattern of lulling himself into a semi-conscious condition by the ritual of reviewing the day with his hands locked behind his head.

Then he swore. It was a pointless habit. He returned his arms to his side and held them rigid, while his head squirmed unpleasantly. Habits could be broken--and any compulsion he had as a result of whatever had happened to him was a luxury he couldn't permit himself.

There would be no recovery until he had overcome the taboos and filled all the gaps in his mind with useful things. Perhaps the Aliens had already succeeded. They might have decided somehow that he was the only man who _could_ solve the problem, and had tampered just enough to make sure he'd fail, while keeping him competent enough to insure that no other man would replace him.

He yanked his arms down again, and started to turn over. Fifteen minutes later, he came out of a complete blackout with his hands at the back of his neck again and a queer feeling that his mind had remained active, with only his memory of its activities missing. His glance darted to the door, but it was still locked, and his clothes lay on the floor where he'd kicked them.

Apparently he hadn't moved from the bed while he'd been short-circuited from his memory, at least.

He thrust himself up from the bed in disgust, pulled on his clothes, and headed down the hall, back towards the laboratory. He passed the cubicle where General Miles should have been sleeping and noticed a trace of light shining under the door. For a second, he remembered the man's words--a spy who confessed would be treated as an honorable prisoner of war.

Only damn it, he wasn't a spy, whatever else he might be. And there was no time left to find someone else to solve the problem that had been dumped into his lap. He couldn't turn himself in while that problem remained a race with death.