"You're crazy, man," snapped Steven Alexander, "you can't take off for Mars alone!"

Scott Nixon thumped the desk in sudden irritation.

"Why not?" he shouted. "One man can run a rocket. Jack Riley's sick and there are no other pilots here. The rocket blasts in fifteen minutes and we can't wait. This is the last chance. The only chance we'll have for months."

Jerry Palmer, sitting in front of the massive radio, reached for a bottle of Scotch and slopped a drink into the tumbler at his elbow.

"Hell, Doc," he said, "let him go. It won't make any difference. He won't reach Mars. He's just going out in space to die like all the rest of them."

Alexander snapped savagely at him. "You don't know what you're saying. You drink too much."

"Forget it, Doc," said Scott. "He's telling the truth. I won't get to Mars, of course. You know what they're saying down in the base camp, don't you? About the bridge of bones. Walking to Mars over a bridge of bones."

The old man stared at him. "You have lost faith? You don't think you'll go to Mars?"

Scott shook his head. "I haven't lost my faith. Someone will get there ... sometime. But it's too soon yet. Look at that tablet, will you!"

He waved his hand at a bronze plate set into the wall.

"The roll of honor," said Scott, bitterly. "Look at the names. You'll have to buy another soon. There won't be room enough."

One Nixon already was on that scroll of bronze. Hugh Nixon, fifty-fourth from the top. And under that the name of Harry Decker, the man who had gone out with him.

The radio blurted suddenly at them, jabbering, squealing, howling in anguish.

Scott stiffened, ears tensed as the code sputtered across millions of miles. But it was the same old routine. The same old message, repeated over and over again ... the same old warning hurled out from the ruddy planet.

" No. No. No come. Danger. "

Scott turned toward the window, started up into the sky at the crimson eye of Mars.

What was the use of keeping hope alive? Hope that Hugh might have reached Mars, that someday the Martian code would bring some word of him.

Hugh had died ... like all the rest of them. Like those whose names were graven in the bronze there on the wall. The maw of space had swallowed him. He had flown into the face of silence and the silence was unbroken.

The door of the office creaked open, letting in a gust of chilly air. Jimmy Baldwin shut the door behind him and looked at them vacantly.

"Nice night to go to Mars," he said.

"You shouldn't be up here, Jimmy," said Alexander gently. "You should be down at the base, tending to your flowers."

"There're lots of flowers on Mars," said Jimmy. "Maybe someday I'll go to Mars and see."

"Wait until somebody else goes first," said Palmer bitterly.

Jimmy turned about, hesitantly, like a man who had a purpose but had forgotten what it was. He moved slowly toward the door and opened it.

"I got to go," he said.

The door closed heavily but the chill did not vanish from the room. For it wasn't the chill of the mountain's peak, but another kind of chill ... a chill that had walked in with Jimmy Baldwin and now refused to leave.

Palmer tipped the bottle, sloshed the whiskey in the glass.

"The greatest pilot that ever lived," he said. "Now look at him!"

"He still holds the record," Alexander reminded the radio operator. "Eight times to the Moon and still alive."

The accident had happened as Jimmy's ship was approaching Earth on that eighth return trip. A tiny meteor had struck the hull, drilling a sharp-cut hole. It had struck Andy Mason, Jimmy's best friend, squarely between the eyes.

The cabin had been filled with the scream of escaping air, had turned cold with the deadly breath of space and frost crystals had danced in front of Jimmy's eyes.

Somehow Jimmy had patched the hole in the hull, had reached Earth in a smashing rocket drive, knowing he had little air, that every minute was a borrowed eternity.

Most pilots would have killed themselves or blown up their ships in that reckless race for Earth, but Jimmy, ace of all the space-men of his day, had made it.

But he had walked from the ship with a blank face and babbling lips. He still lived at the rocket camp because it was home to him. He puttered among his flowers. He watched the rockets come and go without a flutter of expression. And everyone was kind to him, for in his face they read a fate that might be theirs.

"All of us are crazy," said Scott. "Everyone of us. Myself included. That's why I'm blasting off alone."

"I refuse to let you go," said Alexander firmly.

Scott rested his knuckles on the desk. "You can't stop me. I have my orders to make the trip. Whether I go alone or with an assistant pilot makes no difference. That rocket blasts on time, and I'm in it when it goes."

"But it's foolishness," protested Alexander. "You'll go space-mad. Think of the loneliness!"

"Think of the coordinates," snapped Scott. "Delay the blast-off and you have to work out a set of new ones. Days of work and then it'll be too late. Mars will be too far away."

Alexander spread his hands. "All right then. I hope you make it."

Scott turned away but Alexander called him back.

"You're sure of the routine?"

Scott nodded. He knew the routine by heart. So many hours out to the Moon, landing on the Moon to take on extra fuel, taking off for Mars at an exact angle at a certain minute.

"I'll come out and see you off," said Alexander. He heaved himself up and slid into a heavy coat.

Palmer shouted after Scott. "So long, big boy. It was nice knowing you."

Scott shrugged. Palmer was a little drunk and very bitter. He'd watched them go too long. His nerves were wearing out.

Stars shone like hard, bright jewels in the African sky. A sharp wind blew over the summit of Mt. Kenya, a wind that whined among the ice-bound rocks and bit deep into the flesh. Far below blazed the lights of the base camp, hundreds of feet down the slope from the main rocket camp here atop the mountain set squarely on the Earth's equator.

The rasping voice of a radio newscaster came from the open door of the machine shop.

"New York," shrieked the announcer. "Austin Gordon, famous African explorer, announced this afternoon he will leave soon for the Congo valley, where he will investigate reports of a strange metallic city deep in the interior. Natives, bringing reports of the discovery out of the jungle, claim the city is inhabited by strange metallic insects."

Someone slammed the door and the voice was cut off.

Scott hunched into the wind to light a cigarette.

"The explorers are going crazy, too," he said.

Probably, later on in the program the announcer would have mentioned Scott Nixon and Jack Riley would blast off in a few minutes in another attempt to reach Mars. But it would be well along in the program and it wouldn't take much time. Ten years ago Mars had been big news. Today it rated small heads in the press, slight mention on the air.

But the newscaster would have been wrong about Jack Riley. Jack Riley lay in the base camp hospital with an attack of ptomaine. Only an hour before Jack had clasped Scott's hand and grinned at him and wished him luck.

He needed luck. For in this business a man didn't have even an inside chance.

Scott walked toward the tilted rocket. He could hear the crunch of Alexander's feet as the man moved with him.

"It won't be new to you," Alexander was saying, "you've been to the Moon before."

Yes, he had been to the Moon three times and he was still alive. But, then, he had been lucky. Your luck just simply didn't hold forever. There was too much to gamble on in space. Fuel, for one thing. Men had experimented with fuel for ten years now and still the only thing they had was a combination of liquid oxygen and gasoline. They had tried liquid hydrogen but that had proved too cold, too difficult to confine, treacherous to handle, too bulky because of its low density. Liquid oxygen could be put under pressure, condensed into little space. It was safe to handle, safe until it combined with gasoline and then it was sheer death to anything that got within its reach.

Of course, there had been some improvements. Better handling of the fuel, for instance. Combustion chambers stood up better now because they were designed better. Feed lines didn't freeze so readily now as when the first coffins took to space. Rocket motors were more efficient, but still cranky.

But there were other things. Meteors, for one, and you couldn't do much about them. Not until someone designed a screen, and no one had. Radiations were another. Space was full of radiations and, despite the insulating jacket of ozone some of them seeped through.

Scott climbed through the rocket valve and turned to close it. He hesitated for a moment, drinking in the smell and sight of Earth. There wasn't much that one could see. The anxious face of Alexander, the huddled shadows that were watching men, the twinkling base camp lights.

With a curse at his own weakness, Scott slammed the valve lock, twirled it home.

Fitting himself into the shock absorbent chair, he fastened the straps that held him. His right foot reached out and found the trip that would fire the rockets. Then he lifted his wrist in front of his eyes and watched the second hand of the watch.

Ten seconds. Eight. Now five. The hand was creeping up, ticking off the time. It rested on the zero mark and he slammed down his foot. Cruel weight smashed down upon him, driving his body back into the padded chair. His lungs were flattened, the air driven from them. His heart thumped. Nausea seized him, and black mists swam before his eyes. He seemed to be slipping into a midnight chasm and he cried out weakly. His body went limp, sagging in the chair. Twin streams of blood trickled from his nose and down his lip.

He was far out in space when he struggled back to consciousness. For a time he did not stir. Lying in the chair, it took long minutes to realize where he was. Gradually his brain cleared and his eyes focused and made impressions on his senses. Slowly he became aware of the lighted instrument board, of the rectangle of quartz that formed the vision panel. His ears registered the silence that steeped the ship, the weird, deathly silence of outer space.

Weakly he stirred and sat upright, his eyes automatically studying the panel. The fuel pressure was all right, atmospheric pressure was holding, speed was satisfactory.

He leaned back in the chair and waited, resting, storing his strength. Automatically his hand reached up and wiped the blood from his lips and chin.

II

He was in space. Headed for the Moon and from there for Mars. But even the realization of this failed to rouse him from the lethargy of battered body and tortured brain.

Taking off in a rocket was punishment. Severe, terrible punishment. Only men who were perfect physical specimens could attempt it. An imperfect heart would simply stop under the jarring impact of the blast-off.

Some day rockets would be perfected. Some day rockets would rise gently from the Earth, shaking off Earth's gravity by gradual application of power rather than by tremendous thrusts that kicked steel and glass and men out into space.

But not yet, not for many years. Perhaps not for many generations. For many years men would risk their lives in blasting projectiles that ripped loose from the Earth by the sheer savagery of exploding oxygen and gasoline.

A moan came from the rear of the ship, a stifled pitiful moan that brought Scott upright in the chair, tearing with nervous hands at the buckles of his belt.

With belt loosened, body tensed, he waited for a second, hardly believing he had heard the sound. It came again, a piteous human cry.

Scott leaped to his feet, staggered under the lack of gravitation. The rocket was coasting on momentum now and, while its forward motion gave it a simulation of gravity, enough so a man could orient himself, there was in actuality no positive gravity center in the shell.

A bundle of heavy blankets lay in a corner formed by a lashed down pile of boxes ... and the bundle was moving feebly. With a cry in his throat, Scott leaped forward and tore the blankets aside. Under them lay a battered man, crumpled, with a pool of blood soaking into a blanket that lay beneath him. Scott lifted the body. The head flopped over and he stared down into the vacant, blood-streaked face of Jimmy Baldwin.

Jimmy's eyes fluttered open, then closed again. Scott squatted on his heels, wild thoughts hammering in his head. Jimmy's eyes opened again and regarded the pilot. He raised a feeble hand in greeting. The lips moved, but Jimmy's voice was faint.

"Hello, Scott."

"What are you doing here?" Scott demanded fiercely.

"I don't know," said Jimmy weakly. "I don't know. I meant to do something, but I forgot."

Scott rose and took a bottle of water from a case. Wetting his handkerchief, he bathed the bloodied face. His hands ran over Jimmy's body but found no broken bones. It was a wonder the man hadn't been killed outright. Some more Baldwin luck!

"Where are we, Scott?" Jimmy asked.

"We're in space," said Scott. "We're going out to Mars." No use of telling him anything but the truth.

"Space," said Jimmy. "I use to go out in space. Then something happened." He shook his head wearily. Mercifully, the memory of that something had been wiped from his brain.

Half dragging, half carrying, Scott got him to the assistant pilot's seat, strapped him in, gave him a drink of water. Jimmy's eyes closed and he sank back into the cushions. Scott resumed his chair, leaned forward to look out into space.

There was little to see. Space, viewed from any angle, unless one was near a large body, looked pretty much the same. The Moon was still out of his range of vision. It would be hours before it would move upward to intersect the path of the rocket's flight.

Scott leaned back and looked at Jimmy. Apparently the man had sneaked aboard just before the take-off. No one paid much attention to him. Everyone was kind to him and he was allowed to do as he pleased. For he was not insane. The tragedy of those few minutes years before had merely wiped out his memory, given him the outlook of a child.

Perhaps when he had gotten into the ship he had held some reason for his action, but now even that purpose had escaped him. Once again Jimmy Baldwin was a bewildered child's brain in the body of a man.

"Anyway," said Scott, half speaking to himself, half to the silent form, "you're the first rocket stowaway."

They would miss Jimmy back at the camp, would wonder what had happened to him. Perhaps they'd organize a posse and search for him. The possibility was they would never know what happened, for there was slight chance, Scott told himself, that he or Jimmy or the ship would ever get back to Earth again.

Someone else would have to tend Jimmy's flowers now, but probably no one would, for his flowers were the Martian lilies. And Martian lilies no longer were a novelty.

It had been the lilies that started the whole thing, this crazy parade of men who went into space and died.

Slightly over twelve years ago, Dr. Steven Alexander reported that, from his observatory on Mt. Kenya, he had communicated with Mars by ultrashort wave radio. It had been a long and arduous process. First the signals from Earth, repeated in definite series, at definite intervals. And then, finally, the answer from the Red Planet. After months of labor slow understanding came.

" We send you ," signalled the Martians. " We send you. " Over and over again. A meaningless phrase. What were they sending? Slowly Alexander untangled the simple skein of thought. Mars finally messaged: " We send you token! " That word "token" had been hard. It represented thought, an abstract thought.

The world waited breathlessly for the token. Finally it came, a rocket winging its way across space, a rocket that flashed and glinted in the depth of space as it neared Earth. Kept informed of its location by the Martians, Earth's telescopes watched it come. It landed near Mt. Kenya, a roaring, screaming streak of light that flashed across the midnight sky.

Dug up, it yielded an inner container, well-insulated against heat and cold, against radiation and shock. Opened, it was found to contain seeds. Planted, jealously guarded, carefully tended, the seeds grew, were the Martian lilies. They multiplied rapidly, spread quickly over the Earth.

Back on Earth today the Martian lilies grew in every hamlet, clogged the fence rows of every farm. Relieved of whatever natural enemies and checks they might have had on their native planet, they flourished and spread, became a weed that every farmer cursed whole-heartedly.

Their root structure probed deep into the soil. Drought could not kill them. They grew rapidly, springing to full growth almost overnight. They went to unkillable seed. Which was what might have been expected of any plant nurtured on the stubborn soil of Mars. Earth, to the Martian lilies, was a paradise of air and water and sunlight.

And, as if that first token-load had not been enough, the Martians kept on sending rocket loads of seeds. At each opposition the rockets came, each announced by the messages from the Martian transmitter. And each of them landed almost precisely on the spot where the first had landed.

That took mathematics! Mathematics and a superb knowledge of rocketry. The rockets apparently were automatic. There was no intelligence to guide them once they were shot into space. Their courses must have been plotted to the finest detail, with every factor determined in advance. For the Martian rockets were not aimed at Earth as one broad target but at a certain spot on Earth and so far every one of them had hit that mark!

At the rocket camp each Martian rocket was waited anxiously, with the hope it would bring some new pay load. But the rockets never brought anything but seeds ... more Martian lily seeds.

Jimmy stirred restlessly, opened his eyes and looked out the vision plate. But there was no terror in his eyes, no surprise nor regret.

"Space?" he asked.

Scott nodded.

"We're going to the Moon?"

"To the Moon first," said Scott. "From there we go to Mars."

Jimmy lapsed into silence. There was no change upon his face. There never was any change upon his face.

I hope he doesn't make any trouble, Scott told himself. It was bad enough just to have him along. Bad enough to have this added responsibility.

For space flight was a dangerous job. Ever since the International Mars Communication Center had been formed, with Alexander in charge, space had flung men aside. Ship after ship, pilot after pilot. The task, alone, of reaching the Moon had taken terrible toll.

Men had died. Some had died before they reached the Moon, some had died on the Moon but mostly they had died heading back for Earth. For landing on Earth, jockeying a rocket through Earth's dense atmosphere, is a tricky job. Others had died enroute to Mars, ships flaring in space or simply disappearing, going on and on, never coming back. That was the way it had been with Hugh.

And now his brother, Scott, was following the trail that Hugh had blazed, the trail to the Moon and out beyond. Following in a bomb of potential death, with a blank-faced stowaway in the chair beside him.

Half way to Mars and the ship was still intact. Running true to course, running on schedule, flashing through space under the thrust of momentum built up during the blast-out from the Moon.

Half way to Mars and still alive! But too early yet to hope. Perhaps other men had gotten as far as this and then something had happened.

Scott watched the depths of space, the leering, jeering emptiness of star-studded velvet that stretched on and on.

There had been days of waiting and of watching. More days of waiting and of watching loomed ahead.

Waiting for that warning flicker on the instrument panel, that split second warning before red ruin struck as cranky fuel went haywire.

Waiting for the "tick" of a tiny meteor against the ship's steel wall ... the tiny, ringing sound that would be the prelude to disaster.

Waiting for something else ... for that unknown factor of accident that would spatter the ship and the two men in it through many empty miles.

Endless hours of watching and of waiting, hastily snatched cat-naps in the chair, hastily snatched meals. Listening to the babbling Jimmy Baldwin who wondered how his flowers were getting on, speculated on what the boys were doing back in the rocket camp on Earth.

One thing hammered at Scott Nixon's brain ... the message of the Martian radio, the message that had been coming now for many years. " No. No. No come. Danger. " Always that and little else. No explanation of what the danger was. No suggestion for circumventing or correcting that danger. No helpfulness in Earthmen's struggle to cross the miles of space between two neighboring planets.

Almost as if the Martians didn't want Earthmen to come. Almost as if they were trying to discourage space travel. But that would hardly be the case, for the Martians had readily co-operated in establishing communications, had exhibited real intelligence and earnestness in working out the code that flashed words and thoughts across millions of miles.

Without a doubt, had they wished, the Martians could have helped. For it was with seemingly little effort that they sent their own rockets to earth.

And why had each Martian rocket carried the same load each time? Could there be some significance in those Martian lily seeds? Some hidden meaning the Earth had failed to grasp? Some meaning that the things from Mars hoped would be read with each new rocket-load?

Why hadn't the Martians come themselves? If they could shoot automatic rockets across the miles of space, certainly they could navigate rockets carrying themselves.

The Martian rockets had been closely studied back on Earth but had yielded no secrets. The fuel always was exhausted. More than likely the Martians knew, to the last drop, how much was needed. The construction was not unlike Earth rockets, but fashioned of a steel that was hardened and toughened beyond anything Earth could produce.

So for ten years Earthmen had worked unaided to cross the bridge of space, launching ships from the Earth's most favored take-off point, from the top of Mt. Kenya, heading out eastward into space, taking advantage of the mountain's three mile height, the Earth's rotation speed of 500 yards per second at the equator.

Scott reviewed his flight, checked the clocklike routine he had followed. Blast-off from Earth. Landing in the drear, desolate Mare Serenitatis on the Moon, refueling the ship from the buried storage tanks, using the caterpillar tractor from the underground garage to haul the rocket onto the great turn-table cradle. Setting the cradle at the correct angle and direction, blasting off again at the precise second, carrying a full load of fuel, something impossible to do and still take off from Earth. Taking advantage of the Moon's lower gravity, its lack of atmosphere. Using the Moon as a stepping stone to outer space.

Now he was headed for Mars. If he landed there safely, he could spend two days, no more, no less, before he blasted off for Earth again.

But probably he wouldn't reach Mars. Probably he and Jimmy Baldwin, in the end, would be just a few more bones to pave the road to Mars.

III

A gigantic building, rising to several hundred feet in height, domed, without door or window, stood lonely in the vastness of the red plain that stretched to the far-off black horizon.

The building and nothing more. No other single sign of habitation. No other evidence of intelligent life.

The Martian lilies were everywhere, great fields of them, bright scarlet against the redness of the sand. But in its native soil the Martian lily was a sorry thing, a poor apology for the kind of flower that grew on Earth. Stunted, low-growing, with smaller and less brilliant flowers.

The sand gritted under Scott's boots as he took a slow step forward.

So this was Mars! Here, at the North pole ... the single building ... the only evidence of intelligence on the entire planet. As the ship had circled the planet, cutting down its tremendous speed, he had studied the surface in the telescopic glass and this building had been the only habitation he had seen.

It stood there, made of shimmering metal, glinting in the pale sunlight.

"Bugs," said Jimmy, at Scott's elbow.

"What do you mean, bugs?" asked Scott.

"Bugs in the air," said Jimmy. "Flying bugs."

Scott saw them then. Things that looked like streaks of light in the feeble sunshine. Swarms of them hovered about the great building and others darted busily about.

"Bees," suggested Jimmy.

But Scott shook his head. They weren't bees. They glinted and flashed when the sun's light struck them and they seemed more mechanical than life-like.

"Where are the Martians?" Jimmy demanded.

"I don't know, Jimmy," declared Scott. "Damned if I do."

He had envisioned the first Earthmen reaching Mars as receiving thunderous ovation, a mighty welcome from the Martians. But there weren't any Martians. Nothing stirred except the shining bugs and the lilies that nodded in a thin, cold breeze.

There was no sound, no movement. Like a quiet summer afternoon back on Earth, with a veil of quietness drawn over the flaming desert and the shimmering building.

He took another step, walking toward the great building. The sand grated protestingly beneath his boot-heels.

Slowly he approached the building, alert, watching, ready for some evidence that he and Jimmy had been seen. But no sign came. The bugs droned overhead, the lilies nodded sleepily. That was all.

Scott looked at the thermometer strapped to the wrist of his oxygen suit. The needle registered 10 above, Centigrade. Warm enough, but the suits were necessary, for the air was far too thin for human consumption.

Deep shadow lay at the base of the building and as he neared it, Scott made out something that gleamed whitely in the shadow. Something that struck a chord of remembrance in his brain, something he had seen back on Earth.

As he hurried forward he saw it was a cross. A white cross thrust into the sand.

With a cry he broke into a run.

Before the cross he dropped to his knees and read the crudely carved inscription on the wood. Just two words. The name of a man, carven with a jack-knife:

HARRY DECKER

Harry Decker! Scott felt his brain swimming crazily.

Harry Decker here! Harry Decker under the red sand of Mars! But that couldn't be. Harry Decker's name couldn't be here. It was back on Earth, graven on that scroll of bronze. Graven there directly beneath the name of Hugh Nixon.

He staggered to his feet and stood swaying for a moment.

From somewhere far away he heard a shout and swinging around, ran toward the corner of the building.

Rounding it, he stopped in amazement.

There, in the shelter of the building, lay a rusted space ship and running across the sand toward him was a space-suited figure, a figure that yelled as it ran and carried a bag over its shoulder, the bag bouncing at every leap.

"Hugh!" yelled Scott.

And the grotesque figure bellowed back.

"Scott, you old devil! I knew you'd do it! I knew it was you the minute I heard the rocket blasts!"

"It's nice and warm here now," said Hugh, "but you'd ought to spend a winter here. An Arctic blizzard is a gentle breeze compared with the Martian pole in winter time. You don't see the Sun for almost ten months and the mercury goes down to 100 below, Centigrade. Hoar frost piles up three and four feet thick and a man can't stir out of the ship."

He gestured at the bag.

"I was getting ready for another winter. Just like a squirrel. My supplies got low before this spring and I had to find something to store up against another season. I found a half dozen different kinds of bulbs and roots and some berries. I've been gathering them all summer, storing them away."

"But the Martians?" protested Scott. "Wouldn't the Martians help you?"

His brother looked at him curiously.

"The Martians?" he asked.

"Yes, the Martians."

"Scott," Hugh said, "I haven't found the Martians."

Scott stared at him. "Let's get this straight now. You mean you don't know who the Martians are?"

Hugh nodded. "That's exactly it. I tried to find them hard enough. I did all sorts of screwy things to contact that intelligence which talked with the Earth and sent the rockets full of seed, but I've gotten exactly nowhere. I've finally given up."

"Those bugs," suggested Scott. "The shining bugs."

Hugh shook his head. "No soap. I got the same idea and managed to bat down a couple of them. But they're mechanical. That's all. Just machines. Operated by radium.

"It almost drove me nuts at first. Those bugs flying around and the building standing there and the Martian lilies all around, but no signs of any intelligence. I tried to get into the building but there aren't any doors or windows. Just little holes the bugs fly in and out of.

"I couldn't understand a thing. Nothing seemed right. No purpose to any of it. No apparent reason. Only one thing I could understand. Over on the other side of the building I found the cradle that is used to shoot the rockets to Earth. I've watched that done."

"But what happened?" asked Scott. "Why didn't you come back? What happened to the ship?"

"We had no fuel," said Hugh.

Scott nodded his head.

"A meteor in space."

"Not that," Hugh told him, "Harry simply turned the petcocks, let our gasoline run into the sand."

"Good Lord! Was he crazy?"

"That's exactly what he was," Hugh declared. "Batty as a bedbug. Touch of space madness. I felt sorry for him. He cowered like a mad animal, beaten by the sense of loneliness and space. He was afraid of shadows. He got so he didn't act like a man. I was glad for him when he died."

"But even a crazy man would want to get back to Earth!" protested Scott.

"It wasn't Harry," Hugh explained. "It was the Martians, I am sure. Whatever or wherever they are, they probably have intelligences greater than ours. It would be no feat for them, perhaps, to gain control of the brain of a demented man. They might not be able to dominate us, but a man whose thought processes were all tangled up by space madness would be an easy mark for them. They could make him do and think whatever they wanted him to think or do. It wasn't Harry who opened those petcocks, Scott. It was the Martians."

He leaned against the pitted side of the ship and stared up at the massive building.

"I was plenty sore at him when I caught him at it," he said. "I gave him one hell of a beating. I've always been sorry for that."

"What finally happened to him?" asked Scott.

"He ran out of the airlock without his suit," Hugh explained. "It took me half an hour to run him down and bring him back. He took pneumonia. You have to be careful here. Exposure to the Martian atmosphere plays hell with a man's lung tissues. You can breathe it all right ... might even be able to live in it for a few hours, but it's deadly just the same."

"Well, it's all over now," declared Scott. "We'll get my ship squared around and we'll blast off for Earth. We made it here and we can make it back. And you'll be the first man who ever set his foot on Mars."

Hugh grinned. "That will be something, won't it, Scott? But somehow I'm not satisfied. I haven't accomplished a thing. I haven't even found the Martians. I know they're here. An intelligance that's at least capable of thinking along parallel lines with us although its thought processes may not be parallel with ours."

"We'll talk it over later," said Scott. "After we get a cup of coffee into you. I bet you haven't had one in weeks."

"Weeks," jeered Hugh. "Man, it's been ten months."

"Okay, then," said Scott. "Let's round up Jimmy. He must be around here somewhere. I don't like to let him get out of my sight too much."

The silence of the dreaming red deserts was shattered by a smashing report that drummed with a mighty clap against the sky above. A gush of red flame spouted over the domed top of the mighty building and metal shards hammered spitefully against the sides, setting up a metallic undertone to the ear-shattering explosion.

Sick with dread, Scott plunged to the corner of the building and felt the sick dread deepen.

Where his space ship had lain a mighty hole was blasted in the sand. The ship was gone. No part of it was left. It had been torn into tiny fragments and hurled across the desert. Wisps of smoke crept slowly from the pit in the sand, twisting in the air currents that still swirled from the blast.

Scott knew what had happened. There was no need to guess. Only one thing could have happened. The liquid oxygen had united with the gasoline, making an explosive that was sheer death itself. A single tremor, a thrown stone, a vibration ... anything would set it off.

Across the space between himself and the ship came the tattered figure of a man. A man whose clothes were torn. A man covered with blood, weaving, head down, feet dragging.

"Jimmy!" yelled Scott.

He sprinted forward but before he could reach his side, Jimmy had collapsed.

Kneeling beside him, Scott lifted the man's head.

The eyes rolled open and the lips twitched. Slow, tortured words oozed out.

"I'm sorry ... Scott. I don't know why...."

The eyes closed but opened again, a faint flutter, and more words bubbled from the bloody lips.

" I wonder why I did it! "

Scott looked up and saw his brother standing in front of him.

Hugh nodded. "The Martians again, Scott. They could use Jimmy's mind. They could get hold of him. That blasted brain of his...."

Scott looked down at the man in his arms. The head had fallen back, the eyes were staring, blood was dripping on the sand.

"Hugh," he whispered, "Jimmy's dead."

Hugh stared across the sand at the little glimmer of white in the shadow of the building.

"We'll make another cross," he said.

IV

The Martians hadn't wanted them to to come. That much, at least, was clear. But having gotten here, the Martians had no intention of letting them return to Earth again. They didn't want them to carry back the word that it was possible to navigate across space to the outer planet.

Maybe the Martians were committed to a policy of isolation. Maybe there was a "Hands Off" sign set up on Mars. Maybe a "No trespassing" sign.

But if that had been the case, why had the Martians answered the radio calls from Earth? Why had they co-operated with Dr. Alexander in working out the code that made communication possible? And why did they continue sending messages and rockets to the Earth? Why didn't they sever diplomatic relationship entirely, retire into their isolation?

If they didn't want Earthmen to come to Mars why hadn't they trained guns on the two ships as they came down to the scarlet sand, wiped them out without compunction? Why did they resort to the expedient of forcing Earthmen to bring about their own destruction? And why, now that Harry Decker and Jimmy Baldwin were dead, didn't the Martians wipe out the remaining two of the unwanted race?

Perhaps the Martians were merely efficient, not vindictive. Maybe they realized that the remaining two Earthmen constituted no menace? And maybe, on the other hand, the Martians had no weapons. Perhaps they never had held a need for weapons. It might be they had never had to fight for self preservation.

And above and beyond all ... what and where were the Martians? In that huge building? Invisible? In caverns beneath the surface? At some point far away?

Maybe ... perhaps ... why? Speculation and wonderment.

But there was no answer. Not even the slightest hint. Just the building shimmering in the unsetting Sun, the metallic bugs buzzing in the air, the lilies nodding in the breeze that blew across the desert.

Scott Nixon reached the rim of the plateau and lowered the bag of roots from his shoulder, resting and waiting for Hugh to toil up the remaining few yards of the slope.

Before him, slightly over four miles across the plain, loomed the Martian building. Squatting at its base was the battered, pitted space ship. There was too much ozone in the atmosphere here for the steel in the ship to stand up. Before many years had passed it would fall to pieces, would rust away. But that made little difference, for by that time they probably wouldn't need it. By that time another ship would have arrived or they would be dead.

Scott grinned grimly. A hard way to look at things. But the only way. One had to be realistic here. Hard-headed planning was the only thing that would carry them through. The food supply was short and while they'd probably be able to gather enough for the coming winter, there was always the possibility that the next season would find them short.

But there was hope to cling to. Always hope. Hope that the summer would bring another ship winging out of space ... that this time, armed by past experience, they could prevent its destruction.

Hugh came up with Scott, slid the bag of roots to the ground and sat upon it.

He nodded at the building across the desert.

"That's the nerve center of the whole business," he declared. "If we could get into it...." His voice trailed away.

"But we can't," Scott reminded him. "We've tried and we can't. There are no doors. No openings. Just those little holes the bugs fly in and out of."

"There's a door somewhere," said Hugh. "A hidden door. The bugs use it to bring out machines to do the work when they shoot a rocket out for Earth. I've seen the machines. Screwy looking things. Work units pure and simple but so efficient you'd swear they possessed intelligence. I've tried to find the door but I never could and the bugs always waited until I wasn't around before they moved the machines in or out of the building."

He chuckled, scrubbing his bearded face with a horny hand.

"That rocket business saved my life," he said. "If the power lead running out of the building to the cradle hadn't been there I'd been sunk. But there it was, full of good, old electricity. So I just tapped the thing and that gave me plenty of power ... power for heat, for electrolysis, for atmospheric condensation."

Scott sank down heavily on his sack.

"It's enough to drive a man nuts," he declared. "We can reach out and touch the building with our hand. Just a few feet away from the explanation of all this screwiness. Inside that building we'd find things we'd be able to use. Machines, tools...."

Hugh hummed under his breath.

"Maybe," he said, "maybe not. Maybe we couldn't recognize the machines, fathom the tools. Mechanical and technical development here probably wasn't any more parallel to ours than intelligence development."

"There's the rocket cradle," retorted Scott. "Same principle as we use on Earth. And they must have a radio in there. And a telescope. We'd be able to figure them out. Might even be able to send Doc Alexander a message."

"Yeah," agreed Hugh, "I thought of that, too. But we can't get in the building and that settles it."

"The bugs get under my skin," Scott complained. "Always buzzing around. Always busy. But busy at what? Like a bunch of hornets."

"They're the straw bosses of the outfit," declared Hugh. "Carrying out the orders of the Martians. The Martians' hands and eyes you might say."

He dug at the sand with the toe of his space boot.

"Another swarm of them took off just before we started out on this trip," he said. "While you were in the ship. I watched them until they disappeared. Straight up and out until you couldn't see them. Just like they were taking off for space."

He kicked savagely at the sand.

"I sure as hell would like to know where they go," he said.

"There've been quite a few of them leaving lately," said Scott. "As if the building were a hive and they were new swarms of bees. Maybe they're going out to start new living centers. Maybe they're going to build more buildings...."

He stopped and stared straight ahead of him, his eyes unseeing. Going out to start new living centers! Going out to build new buildings! Shining metallic buildings!

Like a cold wind from the past it came to him, a picture of that last night on Earth. He heard the whining wind on Mt. Kenya once again, the blaring of the radio from the machine shop door, the voice of the newscaster.

" Austin Gordon ... Congo Valley ... strange metallic city ... inhabited by strange metallic insects! "

The memory shook him from head to foot, left him cold and shivery with his knowledge.

"Hugh!" he croaked. "Hugh, I know what it's all about!"

His brother stared at him: "Take it easy, kid. Don't let it get you. Stick with me, kid. We're going to make it all right."

"But, Hugh," Scott yelled, "there's nothing wrong with me. Don't you see, I know the answer to all this Martian business now. The lilies are the Martians! Those bugs are migrating to Earth. They're machines. Don't you see ... they could cross space and the lilies would be there to direct them."

He jumped to his feet.

"They're already building cities in the Congo!" he yelled. "Lord knows how many other places. They're taking over the Earth! The Martians are invading the Earth, but Earth doesn't know it!"

"Hold on," Hugh yelled back at him. "How could flowers build cities?"

"They can't," said Scott breathlessly. "But the bugs can. Back on Earth they are wondering why the Martians don't use their rockets to come to Earth. And that's exactly what the Martians are doing. Those rockets full of seeds aren't tokens at all. They're colonization parties!"

"Wait a minute. Slow down," Hugh pleaded. "Tell me this. If the lilies are the Martians and they sent seeds to Earth twelve years ago, why hadn't they sent them before?"

"Because before that it would have been useless," Scott told him. "They had to have someone to open the rockets and plant the seeds for them. We did that. They tricked us into it.

"They may have sent rockets of seeds before but if they did, nothing came of it. For the seeds would have been useless if they weren't taken from the rocket. The rocket probably would have weathered away in time, releasing the seeds but by that time the seeds would have lost their germinating power."

Hugh shook his head.

"It seems impossible," he declared. "Impossible that plants could have real intelligence ... that flowers could hold the mastery of a planet. I'm ready to accept almost any theory but that one...."

"Your mind sticks on parallel evolution," Scott argued. "There's no premise for it. On Earth animals took the spotlight, pushing the plants into a subordinate position. Animals got the head start, jumped the gun on the plants. But there's absolutely no reason why plants should not develop along precisely the same lines here that animals developed on Earth."

"But the Martian lily lives only one season ... ten months ... and then it dies," Hugh protested. "The next season's growth comes from seed. How could plants build intelligence? Each new crop would have to start all over again."

"Not necessarily," declared Scott. "Animals are born with instinct, which is nothing more or less than inherited intelligence. In mankind there are strange evidences of racial memory. Why couldn't the plants do the same thing with their seed ... progress even a step further? Why couldn't the seed carry, along with its other attributes, all the intelligence and knowledge of the preceding generation? That way the new plant wouldn't have to start from scratch, but would start with all the accumulated knowledge of its immediate ancestor ... and would add to that knowledge and pass the sum total on to the generation that was to follow."

Hugh kicked absent-mindedly at the sand.

"There would be advantages in that sort of development," he agreed. "It might even be the logical course of survival on a planet like Mars. Some old Martian race, for all we know, might deliberately have shaped their development toward a plant existence when they realized the conditions toward which the planet was headed."

"A plant society would be a strange one," said Scott. "A sort of totalitarian society. Not the kind of a society animals would build ... for an animal is an individual and a plant is not. In a plant race individuality would count for nothing, the race would count for everything. The driving force would be the preservation and advancement of the race as a whole. That would make a difference."

Hugh glanced up sharply.

"You're damned right that would make a difference," he said. "They would be a deadly race. Once they got started, nothing could stop that singleness of purpose."

His face seemed to blanch under the tan.

"Do you realize what's happening?" he shouted. "For millions of years these plants have fought for bare existence on Mars. Every ounce of their effort has been toward race preservation. Every fall the bugs carefully gather all the seeds and carry them inside the building, bring them out and plant them in the spring. If it hadn't been for some arrangement like that they probably would have died out years ago. Only a few scattered patches of them left now...."

"But on Earth...." said Scott.

And the two of them, white-faced, stared at one another. On Earth the Martian lilies would not have to carry on a desperate fight for their very existence. On Earth they had plenty of water, plenty of sunlight, plenty of good, rich soil. On Earth they grew larger and stronger and straighter. Under such conditions what would be the limit of their alien powers?

With the lilies multiplying each year, growing in every fence row, every garden, crowding out the farmers' crops, lining every stream, clogging every forest ... with swarm after swarm of the metallic bugs driving out into space, heading for the Earth ... what would happen?

How long would the lilies wait? How would they attack? Would they simply crowd out every other living thing, conquering by a sort of population pressure? Or would they develop more fully those powers of forcing animal minds to do their bidding? Or did they have, perhaps, even stronger weapons?

"Hugh," Scott rasped, "we have to warn Earth. Somehow we have to let them know."

"Yes," Hugh agreed, "but how?"

Together, limned against the harsh horizon, they stood, looking across the desert toward the Martian building.

Tiny figures, dimmed by distance, scurried about the building.

Scott squinted his eyes against the desert glare.

"What are those?" he asked.

Hugh seemed to jerk out of a trance.

"The machines again," he said wearily. "They're getting ready to shoot another rocket out to Earth. It'll be the last one of the season. Earth is drawing away again."

"More seeds," said Scott.

Hugh nodded. "More seeds. And more bugs going out. And the worst of it is that Earth doesn't know. No man in his right mind on Earth could even dimly speculate upon the possibility of high intelligence in plant life. There's no reason to. No precedent upon which to base such a speculation. Earth plants have never had intelligence."

"A message is all we need," declared Scott. "Just get word to the Earth. They'd root up every plant on the face of the entire globe. They'd...."

He stopped abruptly and stared out across the desert.

"The rocket," he whispered. "The rocket is going to Earth!"

Hugh swung on him fiercely.

"What are you...."

"We could send a message by the rocket!" yelled Scott. "They always watch for them ... always hoping each one will carry something new. Some new thing from Mars. It's the only way we can get a message back to Earth."

"But they won't let us near," protested Hugh. "I've tried to get up close to the cradle when they were launching one and those machines always drove me away. Didn't hurt me ... but threatened."

"We have guns," said Scott.

"Guns," said Hugh, "wouldn't be worth a damn against them. The bullets would just glance off. Even explosive bullets wouldn't harm them."

"Sledges then," said Scott. "We'll make junk out of the damn things. We've got a couple of sledges in the ship."

Hugh looked at him levelly.

"Okay, kid, let's get going."

V

The machines paid them no attention. No higher than a man's waist, they curiously resembled grotesque spiders. Gangling rods and arms sprouted out all over them and from their trunks sprouted waving, steel antennae.

Overhead hung a swarm of the metallic bugs evidently directing the work of making the rocket ready.

"It takes just three minutes or thereabouts from the time they finally have her ready until she blasts," said Hugh. "Whatever we are going to do has to be done in those three minutes. And we've got to hold them off until the rocket blasts. They'll suspect there's something wrong and will try to stop it but if we can hold them off...."

"They must already have radioed Earth the rocket is coming," said Scott. "We always got word days in advance. Probably they won't follow up with their location messages but Doc will be watching for it anyhow."

They stood tensed, waiting, each grasping a heavy hammer.

The space about the cradle was a scene of intense, but efficient activity. Last minute adjustments were made. Readings and settings were checked. Each machine seemed to act by rote, while overhead hung the cloud of humming bugs.

"We know what we're to do," said Hugh. "We've simply got to do it."

Scott nodded.

Hugh shot a glance at him.

"Think you can hold them off, kid? It'll take a while to unscrew the inner and outer caps and we have got to get that message inside the inner container or it'll burn when the rocket hits atmosphere."

"You just get that message in and the caps back on," said Scott. "I'll hold them off for you."

Suddenly the machines scurried back from the cradle leaving a clear space of several yards around it.

"Now!" Hugh shouted and the two men charged.

The attack was a surprise. Their rush carried the line of machines between them and the cradle.

One machine barred Scott's way and he smashed at it savagely with the heavy hammer. The blow flung it aside, crippled, dented, half-smashed.

Hugh was already at the cradle, clambering up the superstructure.

A machine rushed at Scott, steel arms flailing. Ducking a murderous swipe, the Earthman brought his sledge into play. It sheared through the arms, smashed into the body of the machine. The stricken mechanism seemed to reel, staggered erratically, then collapsed upon the sand.

In two leaps Scott gained the superstructure, scaled it and straddled the cradle. His sledge smashed savagely upon a climbing mechanism, flung it to the ground. But others were swarming up the steel lattice work. Tentacles snaked out, seeking to entrap him. A wicked blow on the leg almost brought him down.

His sledge worked steadily and at the foot of the cradle broken mechanisms bore testimony to its execution.

The spider-machines attacked in a grim deadly silence.

Out of the corner of his eye he saw that Hugh had inserted the envelope carrying the message in the inner container with the seeds, was tightening the screwcap. All that remained was to screw on the larger, heavier outer cap.

But only seconds must remain, precious seconds before the rocket blasted. And before that happened they had to be away from the cradle, for the backlash of flames would burn them to a cinder.

Scott felt perspiration streaming over his body, running off his eyelids, blearing his sight, trickling down his nose. He heard the rasp of metal as Hugh drove home the cap with savage thrusts of the wrench.

A machine rushed up the lattice at him and he smashed at it with unreasoning fury. The head of the sledge bit deep into the metal body.

A tentacle wrapped about his leg and jerked. He felt himself losing his balance, tumbling off the cradle into the melee of threshing metal things beneath him.

Then he was on the ground, buffeted and pounded by the maddened metal creatures. He fought savagely, blindly staggering forward. The shatterproof glass in his vision plate had been "broken," its texture smashed into a million tiny crisscross lines, until it was like frosted glass.

He heard the tough fabric of his suit rip with a screeching sound. The bugs still were hammering against him.

The thin, acrid atmosphere of Mars burned into his nose and his lungs labored.

Unseeingly, he swung his sledge in swathlike circles. Shrieking like a wild Indian, he felt it smash and slam into the bodies of his metallic opponents.

Then the world was blotted out by a resounding roar, a Niagara of sound that beat in waves against one's body.

That was the rocket leaving.

"Hugh!" he yelled insanely. "Hugh, we did it!"

The attack had fallen away and he stood unsteadily on his feet, panting, stiff from punishment, but filled with exultation.

They had won. He and Hugh had sent the message. Earth would be warned and Mars would lose its hope of conquering a new and younger world. Whatever dreams of conquest this old red planet may have nurtured would never come to be.

He put his hands up and ripped the helmet from his head, flinging it on the ground.

The metallic machines were ringed around him, motionless, almost as if they were looking at him. Almost as if they were waiting for his next move.

Wildly he whooped at them. "Start something, damn you! Just start something!"

But the line in front of him parted and he saw the blackened thing that lay upon the sand. The twisted, blasted, crumpled thing that huddled there.

Scott dropped his sledge and a sob rose in his throat. His hands clenched at his side and he tottered slowly forward.

He stood above the body of his brother, flung there on the sand by the searing backlash of the rocket blast.

"Hugh!" he cried, "Hugh!"

But the blackened bundle didn't stir. Hugh Nixon was dead.

Eyes bleared, Scott stared around at the machines. They were breaking up, scattering, moving away.

"Damn you," he screamed, "don't you even care?"

But even as he spoke, he knew they didn't care. The plant civilization of Mars was an unemotional society. It knew no love, no triumph, no defeat, no revenge. It was mechanistic, cold, logical. It did only those things which aimed at a definite end. So long as there was a chance of protecting the rocket, so long as there was hope of halting its flight after it had been tampered with, that civilization would act. But now that it was in space, now that it could not be recalled, the incident was over. There would be no further action.

Scott looked down at the man at his feet.

Harry Decker and Jimmy Baldwin and now Hugh Nixon. Three men had died here on Mars. He was the only one left. And he probably would die, too, for no man could for long breathe that Martian air and live.

What was it Hugh had said that first day?

" It plays hell with the tissues of your lungs. "

He stared around him, saw the interminable red deserts and the scarlet patches of Martian lilies, nodding in the breeze. Saw the humming bugs flashing in the pale sunlight. Saw the shimmer of the mighty building that had no doors or windows.

His lungs were aching now and his throat was raw. It was harder and harder to breathe.

He knelt in the sand and lifted the blackened body. Cradling it in his arms, he staggered along.

"I have to make another cross," he said.

Far overhead, in the depths of space, twinkled the blue planet whose life would never know the slavery of the emotionless race of a dying world.