Mel Gray flung down his hoe with a sudden tigerish fierceness and stood erect. Tom Ward, working beside him, glanced at Gray’s Indianesque profile, the youth of it hardened by war and the hells of the Eros prison blocks.

A quick flash of satisfaction crossed Ward’s dark eyes. Then he grinned and said mockingly.

“Hell of a place to spend the rest of your life, ain’t it?”

Mel Gray stared with slitted blue eyes down the valley. The huge sun of Mercury seared his naked body. Sweat channeled the dust on his skin. His throat ached with thirst. And the bitter landscape mocked him more than Wade’s dark face.

“The rest of my life,” he repeated softly. “The rest of my life!”

He was twenty-eight.

Wade spat in the damp black earth. “You ought to be glad--helping the unfortunate, building a haven for the derelict...”

“Shut up!” Fury rose in Gray, hotter than the boiling springs that ran from the Sunside to water the valleys. He hated Mercury. He hated John Moulton and his daughter Jill, who had conceived this plan of building a new world for the destitute and desperate veterans of the Second Interplanetary War.

“I’ve had enough ‘unselfish service’,” he whispered. “I’m serving myself from now on.”

Escape. That was all he wanted. Escape from these stifling valleys, from the snarl of the wind in the barren crags that towered higher than Everest into airless space. Escape from the surveillance of the twenty guards, the forced companionship of the ninety-nine other veteran-convicts.

Wade poked at the furrows between the sturdy hybrid tubers. “It ain’t possible, kid. Not even for ‘Duke’ Gray, the ‘light-fingered genius who held the Interstellar Police at a standstill for five years’.” He laughed. “I read your publicity.”

Gray stroked slow, earth-stained fingers over his sleek cap of yellow hair. “You think so?” he asked softly.

Dio the Martian came down the furrow, his lean, wiry figure silhouetted against the upper panorama of the valley; the neat rows of vegetables and the green riot of Venusian wheat, dotted with toiling men and their friendly guards.

Dio’s green, narrowed eyes studied Gray’s hard face.

“What’s the matter, Gray? Trying to start something?”

“Suppose I were?” asked Gray silkily. Dio was the unofficial leader of the convict-veterans. There was about his thin body and hatchet face some of the grim determination that had made the Martians cling to their dying world and bring life to it again.

“You volunteered, like the rest of us,” said the Martian. “Haven’t you the guts to stick it?”

“The hell I volunteered! The IPA sent me. And what’s it to you?”

“Only this.” Dio’s green eyes were slitted and ugly. “You’ve only been here a month. The rest of us came nearly a year ago--because we wanted to. We’ve worked like slaves, because we wanted to. In three weeks the crops will be in. The Moulton Project will be self-supporting. Moulton will get his permanent charter, and we’ll be on our way.

“There are ninety-nine of us, Gray, who want the Moulton Project to succeed. We know that that louse Caron of Mars doesn’t want it to, since pitchblende was discovered. We don’t know whether you’re working for him or not, but you’re a troublemaker.

“There isn’t to be any trouble, Gray. We’re not giving the Interplanetary Prison Authority any excuse to revoke its decision and give Caron of Mars a free hand here. We’ll see to anyone who tries it. Understand?”

Mel Gray took one slow step forward, but Ward’s sharp, “Stow it! A guard,” stopped him. The Martian worked back up the furrow. The guard, reassured, strolled back up the valley, squinting at the jagged streak of pale-grey sky that was going black as low clouds formed, only a few hundred feet above the copper cables that ran from cliff to cliff high over their heads.

“Another storm,” growled Ward. “It gets worse as Mercury enters perihelion. Lovely world, ain’t it?”

“Why did you volunteer?” asked Gray, picking up his hoe.

Ward shrugged. “I had my reasons.”

Gray voiced the question that had troubled him since his transfer. “There were hundreds on the waiting list to replace the man who died. Why did they send me, instead?”

“Some fool blunder,” said Ward carelessly. And then, in the same casual tone, “You mean it, about escaping?”

Gray stared at him. “What’s it to you?”

Ward moved closer. “I can help you?”

A stab of mingled hope and wary suspicion transfixed Gray’s heart. Ward’s dark face grinned briefly into his, with a flash of secretive black eyes, and Gray was conscious of distrust.

“What do you mean, help me?”

Dio was working closer, watching them. The first growl of thunder rattled against the cliff faces. It was dark now, the pink flames of the Dark-side aurora visible beyond the valley mouth.

“I’ve got--connections,” returned Ward cryptically. “Interested?”

Gray hesitated. There was too much he couldn’t understand. Moreover, he was a lone wolf. Had been since the Second Interplanetary War wrenched him from the quiet backwater of his country home an eternity of eight years before and hammered him into hardness--a cynic who trusted nobody and nothing but Mel ‘Duke’ Gray.

“If you have connections,” he said slowly, “why don’t you use ‘em yourself?”

“I got my reasons.” Again that secretive grin. “But it’s no hide off you, is it? All you want is to get away.”

That was true. It would do no harm to hear what Ward had to say.

Lightning burst overhead, streaking down to be caught and grounded by the copper cables. The livid flare showed Dio’s face, hard with worry and determination. Gray nodded.

“Tonight, then,” whispered Ward. “In the barracks.”

Out from the cleft where Mel Gray worked, across the flat plain of rock stripped naked by the wind that raved across it, lay the deep valley that sheltered the heart of the Moulton Project.

Hot springs joined to form a steaming river. Vegetation grew savagely under the huge sun. The air, kept at almost constant temperature by the blanketing effect of the hot springs, was stagnant and heavy.

But up above, high over the copper cables that crossed every valley where men ventured, the eternal wind of Mercury screamed and snarled between the naked cliffs.

Three concrete domes crouched on the valley floor, housing barracks, tool-shops, kitchens, store-houses, and executive quarters, connected by underground passages. Beside the smallest dome, joined to it by a heavily barred tunnel, was an insulated hangar, containing the only space ship on Mercury.

In the small dome, John Moulton leaned back from a pile of reports, took a pinch of Martian snuff, sneezed lustily, and said.

“Jill, I think we’ve done it.”

The grey-eyed, black-haired young woman turned from the quartzite window through which she had been watching the gathering storm overhead. The thunder from other valleys reached them as a dim barrage which, at this time of Mercury’s year, was never still.

“I don’t know,” she said. “It seems that nothing can happen now, and yet ... It’s been too easy.”

“Easy!” snorted Moulton. “We’ve broken our backs fighting these valleys. And our nerves, fighting time. But we’ve licked ‘em!”

He rose, shaggy grey hair tousled, grey eyes alight.

“I told the IPA those men weren’t criminals. And I was right. They can’t deny me the charter now. No matter how much Caron of Mars would like to get his claws on this radium.”

He took Jill by the shoulders and shook her, laughing.

“Three weeks, girl, that’s all. First crops ready for harvest, first pay-ore coming out of the mines. In three weeks my permanent charter will have to be granted, according to agreement, and then...

“Jill,” he added solemnly, “we’re seeing the birth of a world.”

“That’s what frightens me.” Jill glanced upward as the first flare of lightning struck down, followed by a crash of thunder that shook the dome.

“So much can happen at a birth. I wish the three weeks were over!”

“Nonsense, girl! What could possibly happen?”

She looked at the copper cables, burning with the electricity running along them, and thought of the one hundred and twenty-two souls in that narrow Twilight Belt--with the fierce heat of the Sunside before them and the spatial cold of the Shadow side at their backs, fighting against wind and storm and heat to build a world to replace the ones the War had taken from them.

“So much could happen,” she whispered. “An accident, an escape...”

The inter-dome telescreen buzzed its signal. Jill, caught in a queer mood of premonition, went to it.

The face of Dio the Martian appeared on the screen, still wet and dirty from the storm-soaked fields, disheveled from his battle across the plain in the chaotic winds.

“I want to see you, Miss Moulton,” he said. “There’s something funny I think you ought to know.”

“Of course,” said Jill, and met her father’s eyes. “I think we’ll see, now, which one of us is right.”

The barracks were quiet, except for the mutter of distant thunder and the heavy breathing of exhausted men. Tom Ward crouched in the darkness by Mel Gray’s bunk.

“You ain’t gonna go soft at the last minute, are you?” he whispered. “Because I can’t afford to take chances.”

“Don’t worry,” Gray returned grimly. “What’s your proposition?”

“I can give you the combination to the lock of the hangar passage. All you have to do is get into Moulton’s office, where the passage door is, and go to it. The ship’s a two-seater. You can get her out of the valley easy.”

Gray’s eyes narrowed in the dark. “What’s the catch?”

“There ain’t none. I swear it.”

“Look, Ward. I’m no fool. Who’s behind this, and why?”

“That don’t make no difference. All you want... ow!“

Gray’s fingers had fastened like steel claws on his wrist.

“I get it, now,” said Gray slowly. “That’s why I was sent here. Somebody wanted me to make trouble for Moulton.” His fingers tightened agonizingly, and his voice sank to a slow drawl.

“I don’t like being a pawn in somebody else’s chess game.”

“Okay, okay! It ain’t my fault. Lemme go.” Ward rubbed his bruised wrist. “Sure, somebody--I ain’t sayin’ who--sent you here, knowin’ you’d want to escape. I’m here to help you. You get free, I get paid, the Big Boy gets what he wants. Okay?”

Gray was silent, scowling in the darkness. Then he said.

“All right. I’ll take a chance.”

“Then listen. You tell Moulton you have a complaint. I’ll...”

Light flooded the dark as the door clanged open. Ward leaped like a startled rabbit, but the light speared him, held him. Ward felt a pulse of excitement beat up in him.

The long ominous shadows of the guards raised elongated guns. The barracks stirred and muttered, like a vast aviary waking.

“Ward and Gray,” said one of the guards. “Moulton wants you.”

Gray rose from his bunk with the lithe, delicate grace of a cat. The monotony of sleep and labor was ended. Something had broken. Life was once again a moving thing.

John Moulton sat behind the untidy desk. Dio the Martian sat grimly against the wall. There was a guard beside him, watching.

Mel Gray noted all this as he and Ward came in. But his cynical blue eyes went beyond, to a door with a ponderous combination lock. Then they were attracted by something else--the tall, slim figure standing against the black quartz panes of the far wall.

It was the first time he had seen Jill Moulton. She looked the perfect sober apostle of righteousness he’d learned to mock. And then he saw the soft cluster of black curls, the curve of her throat above the dark dress, the red lips that balanced her determined jaw and direct grey eyes.

Moulton spoke, his shaggy head hunched between his shoulders.

“Dio tells me that you, Gray, are not a volunteer.”

“Tattletale,” said Gray. He was gauging the distance to the hangar door, the positions of the guards, the time it would take to spin out the combination. And he knew he couldn’t do it.

“What were you and Ward up to when the guards came?”

“I couldn’t sleep,” said Gray amiably. “He was telling me bedtime stories.” Jill Moulton was lovely, he couldn’t deny that. Lovely, but not soft. She gave him an idea.

Moulton’s jaw clamped. “Cut the comedy, Gray. Are you working for Caron of Mars?”

Caron of Mars, chairman of the board of the Interplanetary Prison Authority. Dio had mentioned him. Gray smiled in understanding. Caron of Mars had sent him, Gray, to Mercury. Caron of Mars was helping him, through Ward, to escape. Caron of Mars wanted Mercury for his own purposes--and he could have it.

“In a manner of speaking, Mr. Moulton,” he said gravely, “Caron of Mars is working for me.”

He caught Ward’s sharp hiss of remonstrance. Then Jill Moulton stepped forward.

“Perhaps he doesn’t understand what he’s doing, Father.” Her eyes met Gray’s. “You want to escape, don’t you?”

Gray studied her, grinning as the slow rose flushed her skin, the corners of her mouth tightening with anger.

“Go on,” he said. “You have a nice voice.”

Her eyes narrowed, but she held her temper.

“You must know what that would mean, Gray. There are thousands of veterans in the prisons now. Their offenses are mostly trivial, but the Prison Authority can’t let them go, because they have no jobs, no homes, no money.

“The valleys here are fertile. There are mines rich in copper and pitchblende. The men have a chance for a home and a job, a part in building a new world. We hope to make Mercury an independent, self-governing member of the League of Worlds.”

“With the Moultons as rulers, of course,” Gray murmured.

“If they want us,” answered Jill, deliberately missing the point. “Do you think you have the right to destroy all we’ve worked for?”

Gray was silent. Rather grimly, she went on.

“Caron of Mars would like to see us defeated. He didn’t care about Mercury before radium was discovered. But now he’d like to turn it into a prison mining community, with convict labor, leasing mine grants to corporations and cleaning up big fortunes for himself and his associates.

“Any trouble here will give him an excuse to say that we’ve failed, that the Project is a menace to the Solar System. If you try to escape, you wreck everything we’ve done. If you don’t tell the truth, you may cost thousands of men their futures.

“Do you understand? Will you cooperate?”

Gray said evenly, “I’m my own keeper, now. My brother will have to take care of himself.”

It was ridiculously easy, she was so earnest, so close to him. He had a brief kaleidoscope of impressions--Ward’s sullen bewilderment, Moulton’s angry roar, Dio’s jerky rise to his feet as the guards grabbed for their guns.

Then he had his hands around her slim, firm throat, her body pressed close to his, serving as a shield against bullets.

“Don’t be rash,” he told them all quietly. “I can break her neck quite easily, if I have to. Ward, unlock that door.”

In utter silence, Ward darted over and began to spin the dial. At last he said, “Okay, c’mon.”

Gray realized that he was sweating. Jill was like warm, rigid marble in his hands. And he had another idea.

“I’m going to take the girl as a hostage,” he announced. “If I get safely away, she’ll be turned loose, her health and virtue still intact. Good night.”

The clang of the heavy door had a comforting sound behind them.

The ship was a commercial job, fairly slow but sturdy. Gray strapped Jill Moulton into one of the bucket seats in the control room and then checked the fuel and air gauges. The tanks were full.

“What about you?” he said to Ward. “You can’t go back.”

“Nah. I’ll have to go with you. Warm her up, Duke, while I open the dome.”

He darted out. Gray set the atmosphere motors idling. The dome slid open, showing the flicker of the auroras, where areas of intense heat and cold set up atmospheric tension by rapid fluctuation of adjoining air masses.

Mercury, cutting the vast magnetic field of the Sun in an eccentric orbit, tortured by the daily change from blistering heat to freezing cold in the thin atmosphere, was a powerful generator of electricity.

Ward didn’t come back.

Swearing under his breath, tense for the sound of pursuit in spite of the girl, Gray went to look. Out beyond the hangar, he saw a figure running.

Running hard up into the narrowing cleft of the valley, where natural galleries in the rock of Mercury led to the places where the copper cables were anchored, and farther, into the unexplored mystery of the caves.

Gray scowled, his arrogant Roman profile hard against the flickering aurora. Then he slammed the lock shut.

The ship roared out into the tearing winds of the plain. Gray cut in his rockets and blasted up, into the airless dark among the high peaks.

Jill Moulton hadn’t moved or spoken.

Gray snapped on the space radio, leaving his own screen dark. Presently he picked up signals in a code he didn’t know.

“Listen,” he said. “I knew there was some reason for Ward’s running out on me.”

His Indianesque face hardened. “So that’s the game! They want to make trouble for you by letting me escape and then make themselves heroes by bringing me in, preferably dead.

“They’ve got ships waiting to get me as soon as I clear Mercury, and they’re getting stand-by instructions from somebody on the ground. The somebody that Ward was making for.”

Jill’s breath made a small hiss. “Somebody’s near the Project...”

Gray snapped on his transmitter.

“Duke Gray, calling all ships off Mercury. Will the flagship of your reception committee please come in?”

His screen flickered to life. A man’s face appeared--the middle-aged, soft-fleshed, almost stickily innocent face of one of the Solar Systems greatest crusaders against vice and crime.

Jill Moulton gasped. “Caron of Mars!”

“Ward gave the game away,” said Gray gently. “Too bad.”

The face of Caron of Mars never changed expression. But behind those flesh-hooded eyes was a cunning brain, working at top speed.

“I have a passenger,” Gray went on. “Miss Jill Moulton. I’m responsible for her safety, and I’d hate to have her inconvenienced.”

The tip of a pale tongue flicked across Caron’s pale lips.

“That is a pity,” he said, with the intonation of a preaching minister. “But I cannot stop the machinery set in motion...”

“And besides,” finished Gray acidly, “you think that if Jill Moulton dies with me, it’ll break John Moulton so he won’t fight you at all.”

His lean hand poised on the switch.

“All right, you putrid flesh-tub. Try and catch us!”

The screen went dead. Gray hunched over the controls. If he could get past them, lose himself in the glare of the Sun...

He looked aside at the stony-faced girl beside him. She was studying him contemptuously out of hard gray eyes.

“How,” she said slowly, “can you be such a callous swine?”

“Callous?” He controlled the quite unreasonable anger that rose in him. “Not at all. The war taught me that if I didn’t look out for myself, no one would.”

“And yet you must have started out a human being.”

He laughed.

The ship burst into searing sunlight. The Sunside of Mercury blazed below them. Out toward the velvet dark of space the side of a waiting ship flashed burning silver.

Even as he watched, the flare of its rockets arced against the blackness. They had been sighted.

Gray’s practised eye gauged the stranger’s speed against his own, and he cursed softly. Abruptly he wheeled the ship and started down again, cutting his rockets as the shadow swallowed them. The ship was eerily silent, dropping with a rising scream as the atmosphere touched the hull.

“What are you going to do?” asked Jill almost too quietly.

He didn’t answer. Maneuvering the ship on velocity between those stupendous pinnacles took all his attention. Caron, at least, couldn’t follow him in the dark without exhaust flares as guides.

They swept across the wind-torn plain, into the mouth of the valley where Gray had worked, braking hard to a stop under the cables.

“You might have got past them,” said Jill.

“One chance in a hundred.”

Her mouth twisted. “Afraid to take it?”

He smiled harshly. “I haven’t yet reached the stage where I kill women. You’ll be safe here--the men will find you in the morning. I’m going back, alone.”

“Safe!” she said bitterly. “For what? No matter what happens, the Project is ruined.”

“Don’t worry,” he told her brutally. “You’ll find some other way to make a living.”

Her eyes blazed. “You think that’s all its means to us? Just money and power?” She whispered, “I hope they kill you, Duke Gray!”

He rose lazily and opened the air lock, then turned and freed her. And, sharply, the valley was bathed in a burst of light.

“Damn!” Gray picked up the sound of air motors overhead. “They must have had infra-red search beams. Well, that does it. We’ll have to run for it, since this bus isn’t armed.”

With eerie irrelevancy, the teleradio buzzed. At this time of night, after the evening storms, some communication was possible.

Gray had a hunch. He opened the switch, and the face of John Moulton appeared on the screen. It was white and oddly still.

“Our guards saw your ship cross the plain,” said Moulton quietly. “The men of the Project, led by Dio, are coming for you. I sent them, because I have decided that the life of my daughter is less important than the lives of many thousands of people.

“I appeal to you, Gray, to let her go. Her life won’t save you. And it’s very precious to me.”

Caron’s ship swept over, low above the cables, and the grinding concussion of a bomb lifted the ship, hurled it down with the stern end twisted to uselessness. The screen went dead.

Gray caught the half stunned girl. “I wish to heaven I could get rid of you!” he grated. “And I don’t know why I don’t!”

But she was with him when he set out down the valley, making for the cliff caves, up where the copper cables were anchored.

Caron’s ship, a fast, small fighter, wheeled between the cliffs and turned back. Gray dropped flat, holding the girl down. Bombs pelted them with dirt and uprooted vegetables, started fires in the wheat. The pilot found a big enough break in the cables and came in for a landing.

Gray was up and running again. He knew the way into the explored galleries. From there on, it was anybody’s guess.

Caron was brazen enough about it. The subtle way had failed. Now he was going all out. And he was really quite safe. With the broken cables to act as conductors, the first thunderstorm would obliterate all proof of his activities in this valley. Mercury, because of its high electrical potential, was cut off from communication with other worlds. Moulton, even if he had knowledge of what went on, could not send for help.

Gray wondered briefly what Caron intended to do in case he, Gray, made good his escape. That outpost in the main valley, for which Ward had been heading, wasn’t kept for fun. Besides, Caron was too smart to have only one string to his bow.

Shouts, the spatter of shots around them. The narrow trail loomed above. Gray sent the girl scrambling up.