Everywhere in Leiccsenland the farms were burning. Silvery Callistan ships, slim arrows of destruction, flew above the countryside methodically. Splendid grain and hay crops were blazing. Barns and dwellings, too.

The thin, clear air trailed streamers of blue smoke, that blurred the ringed globe of monster Saturn, visible at the horizon, above the craggy surrounding hills.

The Earth-Colony here on Titan, largest of Saturn's satellites, seemed doomed. The invaders were firing everything they could reach.

Angry farmers were gathered in front of the Community Bank in Leiccsendale. Old Arne Reynaud, who kept a great orchard and flower-garden beyond the village outskirts, stood on the concrete steps of the bank building, and shouted to the assembled group of bitter faces.

"Twenty-three Earth-years, Terrestrials have been here in Leiccsenland!" he shrilled grimly. "Ain't nobody gonna drive us out now! Not even these damned Callistans from their moon back Jupiter-way! Titan, so far from the sun, was a frozen world when we came. Its water was ice. Even its air lay in frozen snowdrifts in the awful cold! We slaved and starved and spent almost every cent we had, getting started here! Setting up Bart Mallory's atomic sun-ray towers, to make the climate warm! Cultivating the soil, that hadn't had any life in it for a billion years, since Saturn cooled too much to radiate any heat to Titan! Bringing in seeds and cattle and hogs! Even bumble-bees to pollinate the flowers! Ain't no dirty, fuzzy Callistan devils gonna take Titan away from us now! We made us a little heaven, here, with the sweat of our brows! And we're gonna keep it! Ain't no—"

Arne Reynaud got this far in his speech, his shrill, scratchy old voice vibrant with mingled grief and wild determination. But just then a second voice, from the rear of the little crowd, cut in like a whetted knife-blade, keen and caustic and condemning:

"Shut up, Reynaud! That Iron-Made language of yours is completely out of place, now! It only makes things worse! So, for God's sake, shut up! Stop talking like a damned fool!"

The words fairly snapped and snarled with bitterness. No Callistan heat-bomb, dropped into the center of the little gathering itself, could have produced more emotional startlement. Two hundred pairs of haggard eyes turned as one toward the man who had broken a spell. Surprise was too great to allow anger to awaken, yet. There was only wonder as to who this rude traitor could be.

He stood there at the edge of the side-walk, with half his gaunt weight leaned against a maple sapling. But his eyes glowed tensely, under a broad-brimmed colonial hat, denying the indolence of his posture. A crooked smile showed white teeth, and traced a line of derision in one narrow, bronzed cheek. Youth and strength and sadness and broken dreams, were in the curve of his brow and lips. But above all, there was realism—the will to do the best, most reasonable thing, in the face of heart-breaking defeat.

A girl, as forceful as himself—in her own pert way—was the one who answered him. "You!" she stormed. "You—Ron Leiccsen—nephew of the man who explored this world, and died from the effects of hardships here, soon after his return to Earth! The man who made our Titanian Colony possible! And you tell Arne Reynaud to shut up, when he talks patriotism! You're not fit to bear the same name as Jan Leiccsen!"

The girl was Anna Charles, a teacher in the school at the village. There was a moment of strained silence, after her furious, accusing words tumbled out. Her tiny fists were clutched so firmly that the knuckles showed white. Her heart-shaped face had gone pale with fury, defiance, contempt! Her dark eyes blazed narrowly, and her whole, small, reckless body trembled with emotion. Anna Charles, daughter of a champion space pilot, killed several years before, was a tornado from her golden head to the tips of her tiny boots!

But she was only part of the situation, now. Everyone, among those hard, bristly-cheeked colonists, waited for Ron Leiccsen to answer the girl's withering challenge. Ron had been a respected machinist bearing an honored name—before. But his caustic attitude, now, made a difference. Most of those grim men scowled at him. Many of them fingered their smooth, trim-barreled atom-rifles in a silent threat to a dissenter. Even old Arne Reynaud, on his impromptu orator's rostrum before the Community Bank, said nothing. His withered features only looked startled. His thin shoulders sagged in his shapeless overcoat.

The nearest great sun-ray globe, rising on its tall, steel-girdered tower above Leiccsendale, purred softly, shedding its warmth and brilliant light, and its special, invisible radiations, which acted as a stimulus to all vegetable growth, over the scene. Smoke from rich, ripe cornfields nearby, tanged in the cool air, like a questioning ghost. Even the far-off sun itself, scarcely more than a great star in the vast distance, seemed to wait, to see what would happen during the next tense moment.

Ron Leiccsen's grin became a trifle more crooked. Otherwise he scarcely moved, though his eyes admired Anna Charles' vigorous spirit.

"I apologize, if I've hurt anyone's feelings—without good reason," he said at last. "I look up to anyone with plenty of nerve, like Arne Reynaud, or Miss Charles, here. But we can't successfully fight Callistan heat-bombs, and their horde of heavily armed ships. We can't expect any aid from Earth, since the Callistan space navy is supreme in this part of the void. To continue to resist alone, is just plain stupid. We'd all be killed or enslaved—Titan taken away from us anyway, in the end. And we have women and kids, remember! Miss Charles, who is a school teacher, should know that we have kids, here, as well as anybody else! Tots. Who wants to see them enslaved, abused, massacred? So, though it will hurt plenty to do it, let's face facts! Let's leave Titan before these laughing devils from Callisto can fly so many war-craft out from their world that even escape will be cut off!"

Ron Leiccsen paused for just a moment, to let his arguments sink home, and to let the grim truth register in the minds of his hard, embattled listeners. Then he went on.

"Of course, if Arne Reynaud has any information," he said, "any new trick, or any means at all that might give us hope of defeating these furry giants from Jupiter's outermost large moon, let him speak up! Otherwise his talk of fighting is exactly what I implied before—just senseless, foolish courage!"

When Ron Leiccsen finished speaking, farmers looked at each other, their faces puzzled. It was easy to see that common-sense was tempering their defiance against the Callistan hordes, now. Their wives. Their children. Even Anna Charles' features showed a sheepish, apologetic petulance for a moment, as though maybe she realized that the man whom she had as good as accused of traitorous cowardice, might have told the truth.

From the distance, over the blazing fields and farm buildings, a slim, silvery shape flew silently, coming closer. And the atom-guns which had so far kept the hamlet of Leiccsendale itself, safe from the bombs and heat-rays of the Callistan raiders, began to spit their whining darts up from the village outskirts.

But now old Arne Reynaud lifted a shaky hand. "Ron Leiccsen," he shouted sincerely, "you got real, honest-to-gosh, good judgment! Talk without backing don't get anybody anywhere! But I haven't been just shooting off my mouth! There is a way to lick them damned Callistans, as I was gonna tell you all before! Everything's fixed, except for the last tough part of the job!"

It was Ron Leiccsen's turn to be surprised, now. His brows creased in mingled doubt and hope. He stood erect now, taut and ready.

"All right, Arne," he urged eagerly. "I'll eat those words of mine, down to the last sour syllable, if I've said anything out of place! Tell us what you've got up your sleeve."

"Just this, friends," Arne returned seriously. "Mighty few Callistans ever visit Earth. Even though they're immune to our germ diseases, they don't thrive so well there, at certain seasons. Me and a brother of mine, back home, are probably the only men, either Earthian or Callistan, who realize why Callistans get very sick at certain times on Earth, though it's so simple. I saw one die once, in New York State, in summer. It ain't just the density of the air. They can stand that. It's something else—and I've got the password. I found out.

"Quite a while ago, I wrote a letter to my brother. But everybody knew, already, that the trouble with the Callistans was coming. My brother has quite a lot of money, and I asked him to do me a favor. Just a few hours ago I got his space-radiogram, probably one of the last that got through the Callistan interference barrages."

Arne had taken a slip of yellow paper from his pocket. He cleared his throat, and read the message aloud:

"'Dear Arne: Shipload of stuff you asked for is at Vananis, on Mars. Have just learned that crew deserted, refusing to go farther into zone patrolled by hostile Callistan craft. Delivery up to you colonists. Luck. Tony.'"

Arne Reynaud ran his fingers through his ragged gray hair, as he finished the radiogram. "You see, folks?" he continued. "That space freighter is waiting on Mars right now, for somebody to go and get it. All we have to do is sprinkle its cargo all over Leiccsenland, and as much more of Titan as we can...."

The old horticulturist's words were cut short here, as the silvery Callistan ship that had been approaching, swept close, overhead. It had won through the outer defenses of the village. The ominous shadow of the craft, which was small but deadly, slid swiftly over the ground. Sparks of molten metal shot from the tower of the sun-ray globe, as an unseen sword-beam of intense heat lashed at its girders. Steel crumpled and snapped. There was an ugly, creaking, groaning sound, like that which a great tree makes when it begins to fall, after the lumber-jacks have severed its trunk. The tower leaned, like a man shot, and crashed with a thunderous noise onto a row of stores and houses along the street.

Fire spurted, as the great sun-ray globe of heat-resistent carbon-glass shattered, spilling its seething, white-hot contents on the wreckage. Flames lashed up, blazing furiously.

Everyone had crouched down, seeking whatever cover was available, as the enemy ship, glinting in the pale sunshine, and reflecting the glare of the conflagration, circled above. The hiss of its propelling mechanism was almost a whisper. So low that the wild, challenging laughter of the gray-furred Callistan pilot, leaning over its side, could be plainly heard.

The beam of heat that had wrecked the tower, swung downward. It hit the front of the Community Bank, and the latter's windows, with the gold lettering on them, cracked and wilted. Old Arne Reynaud, hunched now behind the stone blocks that flanked the steps, was hit. His whole back was raked by that invisible sword of concentrated heat waves. Flesh and clothing alike was burned away from his spine.

But even as this was happening, slender atom-rifles and pistols were brought into play—sobbing and whirring. Ron Leiccsen was among the other marksmen, firing with his pistol from beneath the foliage of the maple sapling, where he had drawn Anna Charles.

The swift missiles struck the invader craft. Incandescent spots, bluer and more eye-hurting than the glare of an electric arc, blotched its burnished hull. It sagged in its flight like a mass of wet paper, and plummeted to the street. From the wreck was hurled a big-chested, furry, half-human form, bloodied, and spattered with its own brains, its broken, slender limbs tangled in the wires of a house-yard fence.

Ron Leiccsen leaped to where Arne Reynaud lay on the heat-racked bank steps. There was still a flicker of life in his faded blue eyes, glazed with agony. But he was past all help.

"Ron," he muttered, as the youth bent over him. "You didn't believe me—anyhow at first.... But I ain't a liar.... I told the truth.... Mars.... That ship there.... Do what I said—please.... It'll lick the Callistans.... You got nerve—cleverness—plenty. A swell space-pilot, too—the others aren't so good.... Bring the freighter to Titan.... Sprinkle the stuff in the hold all over Leiccsenland.... The cargo is—is...."

And there old Arne's heart stopped beating. His charred body relaxed in its last sleep. His brain ceased to think. And a vast question-mark seemed to hang over him. While in Leiccsenland, chaos thundered. Fire crackled and roared.

Anna Charles was bending close to the old man's body, too, her face a mask of dumb horror. But she had become challenging again, now. "You heard what he said, didn't you, Ron Leiccsen?" she flung at him with a taut, cold softness. "Your idea that we should all leave Titan may be wrong! There's that ship on Mars, which might save our colony! And he—Arne—appointed you to go and bring it here!"

No one could ever have traced the course of the tumultuous hatred and doubt that seethed in Ron Leiccsen's mind just then. Red hate of the laughing fiends of Callisto! Little, withered Arne Reynaud—murdered! He was a hero—an inspiration! And yet, maybe he was just an old fool with an empty, hair-brained scheme that wouldn't work! Another crackpot—a kind of fanatical inventor, perhaps, who deluded himself into believing in a worthless idea! A ship on Mars, loaded with something. What?

Ron struggled to be reasonable, fighting the mad fury that prompted him to be rash, to believe what the old horticulturist had said and fly to Mars. Such action might give the colonists here on Titan false hope. Hope that would encourage them to stay, when maybe they should be leaving with their wives and children.

"It's stupid!" Ron growled at last. "A shipload of some kind of mysterious elixer! Scatter the stuff around on Titan! It'll defeat the Callistans! Bunk! What kind of a magic charm is this, anyway? Arne was a swell old guy, all right; but he fussed too much with his flower garden, and dreamed and wished too much!" All of Ron's cynical, bitter, doubting viewpoint, seemed to boil from his lips. "I've got to see that the colonists leave Titan!"

"I won't leave for one!" Edward Clay, a hard-bitten young farmer with a craggy jaw, stated definitely. "Me and Pa and my wife have been here five years. Not a chance of me going, now! I'll stick, if only to even the odds for Arne Reynaud! Maybe he was an idiot, but he had courage!"

Bart Mallory, who had invented the atomic sun-ray towers, and held their patent rights for the exclusive use of the Titan Colony, was present, too. All of his small, nervous body, even his neatly kept Van Dyke beard, trembled with rage and grief.

"Arne was a good, practical man, when it came to taking care of fruit trees," he said. "But he was certainly no highly trained scientist. I haven't much faith in whatever his idea can be, either. Still, he was my friend. If I ran away from Titan, now that he's been killed, I'd feel like a dirty, yellow coward!"

Most of the other farmers had left the front of the bank building, to fight the fire across the street. But several of those who remained, nodded agreement with Bart Mallory. After all, everything they owned was on Titan. It was their home.

"If you don't go to Mars for that ship, Ron Leiccsen," Anna Charles said quietly, "I will! I know how to fly space-crafts as well as you do, anyway. My father was a racing pilot, and he taught me a few tricks of the trade! What Arne Reynaud said may be bunk; but there's a chance!"

Ron Leiccsen only growled inarticulately, and hurried off toward the blazing buildings. He had to fight something to expend some of his physical energies so that he could think, and clear his brain. Fighting the fire might do this. The release of atomic heat in the incandescent substance from the shattered sun-ray globe had ceased when the tower had collapsed; for the catalytic forces which induced the breakdown of the atoms had been cut off with the disruption of the apparatus. But the spilled contents of the globe were still terrifically hot. Only sand, poured on that dazzling fury, could cool and insulate it. And water was needed to quench the blazing debris of the buildings. So Ron Leiccsen worked like a demon with the other men.

And from the village jailhouse, opposite the row of fire-wracked ruins, hollow, booming laughter mocked him. There a Callistan combat pilot, captured some time ago when his ship had been shot down, clutched the bars of his prison's window with slender, furry, three-fingered hands, and made derisive, gloating remarks in his sketchy English.

"Eart'men! Vaah!" he taunted, his words rumbling in his vast chest. "Very little while—all done—you—here—Titan! Titan be—Mado-Achar—New Achar—New Callisto! Very little while we build shiny metal house here! You find out! You know already! Eart'men! Vaah! Huah!"

And then he would laugh, the breath sizzling in his wide nostrils, his little, close-set eyes, that peeped, like a poodle-dog's through the thick fur that covered his face, reflecting the flames and seeming to glow in appreciation of the situation, and of the choice Acharian insults he had hurled.

As he helped fight down the fire, Ron Leiccsen glanced often toward the defiant captive, wondering intently about all his kind. Tough and hardy, and immune to all terrestrial germ diseases, the Callistans came from a strange world of spore-plants and burnished, bizarre cities, over which a steady, cool climate brooded. Achar—Callisto—being a satellite of Jupiter, was far from the sun, too. But because Achar had a radioactive core, generating heat constantly, its surface was far warmer than would otherwise have been possible. And so there was life, there. It was a different kind of life, in many minor respects, than that of Earth. In that thin, cool atmosphere, nature had omitted certain biological phenomena.

Others of the fire-fighters hurled insults back at the captive Callistan—furious, defiant curses which showed that no sane argument could ever win a good half of them to retreat.

Anna Charles was climbing into the cabin of her sleek, black space flier, which rested on the landing platform on the flat roof of the house where she lived.

She was prepared to seal the door, when a booted foot was thrust against it, preventing her action. A slow, admiring grin was turned upon her. The sullen, half-humorous line in the intruder's bronzed cheek, was like a steel wall, against which her fury and her surprise and contempt lashed in vain.

"Ron Leiccsen!" she choked. "I was ready to start for Mars! What do you want? You and your negative talk!"

Ron entered the ship's cabin. "To Mars, then," he drawled. "But not all by yourself. You see, I've changed my mind, Miss Charles. About half the colonists will stay on Titan, no matter what advice is given, though I hope they'll have sense enough to get most of the kids out. Result of this stubbornness, as far as they're concerned—well—Arne Reynaud's shipload of I-don't-know-what is the one barely possible salvation. So, not being able to rescue my friends with argument, I have no choice. If I deserted them now, I'd only prove myself to be the yellow rat you seem to think I am. Anyway, this trick of bringing that ship back from Mars, is a real, man-size job."

Deliberately, Ron closed the flier's door. He worked the controls. The ship shot up over the blackened, smoke-wreathed plains of Leiccsenland, where splendid corn and grain had grown, under the stimulus of special vitalizing radiations, mixed with the ordinary light and heat that Bart Mallory's sun-ray globes emitted.

In a twinkling, Leiccsenland and Titan were dwindling away, below. In brief minutes, even the bulk of giant Saturn and his Rings and ten glowing moons were shrinking away astern. Ahead was the tiny sun, Mars and Earth and Venus completely lost in its rays.

"Pray for speed, Miss Charles," Ron grated grimly. "Pray that we make this trip in time! And that Arne Reynaud's idea is something better than the froth of an addled brain!"

Their velocity was demoniac. But the distance they had to go was tremendous. They plotted a course across the orbit of Jupiter, and through the dangerous Belt of Asteroids. Luckily, Mars and Saturn, in their respective orbital positions, were near their closest possible approach to each other. So the journey was about as short as it could ever be.

The spacial stars leered sardonically, and Ron and Anna stuck to their posts like fiends, charting, piloting, keeping watch for meteors in that dangerous region of cosmic debris, the Asteroid Belt. There was no time for quarreling, there was no time for sentiment, there was little enough time to eat, and only moments for sleep.

Thus they reached Vananis, the gigantic spaceport set amidst the rusty red deserts of Mars. But even then it was only the beginning. Two Earth-weeks it had taken to come. And it would take longer to return; for on their trip back their ship would not be a slim scout, but a heavy freighter instead.

They were directed to it there at the quays. The Barbarian was the name painted on its beetling black prow. It was a black ship, as were all the space craft of Earth—slender, quite speedy, judging from its lines and the power rating of its engines and gravity repulsion plates. It was an old grain-carrying ship. Its cargo hatches were battened down firmly, and could not easily have been removed.

"What does its cargo consist of?" Ron Leiccsen asked, after Anna and he had presented their credentials, identifying themselves as Titanian colonists and licensed space pilots—the only necessary formalities in their taking control of the freighter; for special orders had been radioed to Mars by Arne Reynaud's brother, weeks before.

"I don't know what the cargo is," the brown-skinned Martian official returned indifferently. "You realize the crew deserted, not caring to go any nearer to Titan, with the Callistan trouble brewing. And we don't care especially what the Barbarian's hold contains, so long as it's not going to be unloaded here in Vananis."

There was no time for further investigations of what the tightly closed hatches might conceal. It would have been useless to attempt to radio Earth, and try to find out from Arne Reynaud's brother; for that would take an hour at least, and besides, there was a barrage of static even in this region, thrown out from a great station on Callisto as a wartime blockade measure. No message could have gotten through.

Ron Leiccsen and Anna Charles cast longing, wondering glances at the huge grain discharge-spout, under the flairing stern of the craft. But there were no precious minutes to spare, to investigate what lay beyond that spout, within the bowels of the ship, itself. They begrudged even the moments it took to climb the narrow ladders to the control turret of the Barbarian.

At Ron's manipulation of switches and levers, the engines that fed power to the gravity plates began to whine. Like a black cloud, the old freighter arose from the quays.

The first part of the trip back toward Titan was quite uneventful, though the work and vigilance involved in bringing a huge, clumsy, and far under-manned ship along a perilous, short-cut route through the region of the asteroids, was even more gruelling than the journey in the scout flier had been. Luckily, most of the machinery was automatic, needing almost no attention to keep it functioning.

But Ron Leiccsen knew what kind of trouble lay ahead. So did Anna Charles. By now many more silvery ships must have gone out from Callisto toward Saturn and Titan to reinforce the conquering hordes already there.

"We'll make it, all right, Ron," Anna declared vehemently, showing almost her first signs of friendship toward her companion. "We'll make it because we've got to!"

Her small, red lips jutted out petulantly. She was coaxing herself into a mood of optimism with defiance alone. She was being optimistic only by wanting to be.

"Maybe we'll make it!" Ron Leiccsen answered doubtfully. "If our luck is right, and if we work out a good enough plan!"

"Why, what do you mean?" she snapped back at him, angry again because of his usual dark thinking, which seemed to laugh at hope.

"Just what I say," he returned brutally, feeling that he might have tried to keep the grim facts from her, if she'd been less reckless by nature. But she was no fragile clinging vine. Bleak, skeletal truth might help to balance her judgment of what was wise and what was not.

"I guess you're right," Anna Charles murmured at last, her sagging shoulders showing suddenly how very tired she was, and how little. "Those Callistan ships are almost certain to spot us, as we approach Titan. They can recognize a black Earth-craft from millions of miles off, through their telescopes. They'll try to get us, of course, and unless we find some way to trick them, we'll never win through the blockade alive!"

Ron patted Anna's arm, and grinned reassuringly. She was not reckless now, though she betrayed no hint of real fear.

Suddenly Ron wanted very much to kiss Anna Charles; but he didn't do it. "We'll think hard, pal," he said quietly, almost apologetically, "and maybe we'll find a way to reach Titan, yet!"

Thinking—with the sharp, steady stars gleaming ahead. Thinking—with Saturn and his beady moors growing, getting closer, out of the distance of space. Danger, coming nearer and nearer. Ron Leiccsen's head ached with fatigue, with mental strain, with somber doubts. There was no way to hide this huge, black Earth-freighter from keen Callistan eyes. No way at all! And yet he had to keep trying. Struggling to build a scheme to run the blockade and elude the mathematical accuracy of the long-range atom guns which the Callistans used in space fighting. The Barbarian was unarmed, and against such guns, within any range less than two hundred miles, it wouldn't have a chance.

There was still no time to investigate the freighter's unknown cargo. To do so would have involved the unbolting of massive doors, hasped and sealed for the voyage, so that there would be no danger that the load would shift, throwing the ship off balance, and disturbing its flight. A couple of hours' work would be required to unscrew those bolts, and replace them again, for safety. And there might be other unknown dangers, too.

Ron decided to put the question of the cargo's value as a weapon out of his mind. Arne Reynaud's mysterious idea, in which he still felt scant confidence, would either fail or succeed—that is, if they got through to Titan. And there was no use seeking an easily possible unhappy disillusionment, now. Not when the cargo was the only hope of Titan Colony! He and Anna were pledged to deliver it, and to scatter it over and around Leiccsenland. That was their part of the job. If they accomplished the job, without any hoped-for result against the men of Achar—well—he couldn't help that.

They were only a million miles from Saturn, when danger finally became visible. Anna, at the lookout telescope, gave the warning, her lips atremble.

"I see them," she said. "Bright silvery dots against space. Callistan ships, maybe fifty of them, ahead and to port about a million and a quarter miles. They're coming this way, rapidly."

"They must have spotted us already, then," Ron stated with a slow, surly nod. "Even a black ship reflects enough sunlight to be seen easily from a long way off, through a telescope."

He moved the guide-levers, heading the ship to the right of Saturn's colossal, whirling bulk. Titan was to the left of the planet now, and far out.

After all his thinking, Ron had only one pathetic shadow of an idea to use against the enemy. By going to the right of Saturn, instead of to the left, he was avoiding the direct route to Titan, cherishing the forlorn hope that such action might confuse the Acharians a little, and perhaps enable the Barbarian to circle the gigantic gaseous world, and somehow reach Titan from the other side.

The engines of the freighter were throbbing and vibrating hideously, feeding every ounce of power they could produce, to the gravity plates, that hurled their propelling beams of reversed force, astern. Speed! Speed! Ron's fingernails bit savagely into his palms, as he guided the old freighter on, as fast as he could make her go.

"The Callistan ships are trying to close in ahead of us," Anna announced from the telescope.

"I guess they see, then, what I'm trying to do," Ron commented bitterly. "And they're twenty-percent more speedy than we are."

He didn't change his course. To do so would have been useless. He just kept driving the old merchantman on, determined to make it as good a race as possible.

Saturn bulked more and more huge in the ship's observation bay. Ron's course took him straight to the edge of those vast, arcing circular paths of cosmic dust and pebbles, known as the Rings. Seen from the Barbarian's angle of approach, the planet's northern hemisphere was upward.

There, just beyond the stupendous natural miracle of the Rings, thousands of miles across, Ron piloted his craft along, in a parallel curve around Saturn. Anna and he had gotten this far, at least, ahead of their enemies; but what good did that do?

Scarcely half a mile in front of the freighter, a terrific explosion blazed soundlessly in the voidal vacuum. Then another and another. A little nearer each time. The Acharian fleet was firing explosive atomic shells at its prey. In greater and greater numbers, as each second passed, and with better and better accuracy, as sighting instruments and ballistics calculating machines improved the aim.

There was no way for Ron and Anna to return the fire. In spite of her war-like name, the old merchantman carried no weapons. She had been sent out from Earth on her strange errand too hastily to be fitted with guns. But even had she been a battleship, her position would have been hopeless against the odds of fifty to one!

Once the Barbarian's hull rung and shivered like a vast, deep-throated bell, as an exploding projectile barely grazed her flanks. It was a matter of moments, now, before a direct and final hit would be made. The atomic missiles the Callistans were using, were different in their action from the silent, metal-melting darts employed in the rifles of the terrestrial colonists of Titan. But they were no less effective, in their more sudden release of atomic power, because of that!

Young Leiccsen found himself looking into Anna Charles' brave, misty eyes. The pale, flooding glow of Saturn, and its sinister Rings, reflecting the sunlight, streamed through the broad observation bay of the control turret, and touched her hair, making it give back soft, golden glints.

"Ron," she said quietly, "I guess this is the end of the trail. But I wouldn't like to let it be those devils from Callisto who kill us. I'd rather choose the way to die. Maybe you would, too. There's another road out of this life, Ronnie. A grander one. You're so bitter, sometimes. But I think you're like me, in a few things. Shall we go—that other way? It's so close, so easy, so swift. Look...."

She was pointing through the observation bay, straight into that awesome flood of reflected sunshine. Not at Saturn itself, whirling like a giant, streaked orb that filled almost half the spacial sky. But at the Rings.

No words could ever have described that incredible spectacle—perhaps the greatest natural wonder in all explored space! A tremendous, sweeping path, circling in a perfect plane, like a highway of the gods. Misty at the edges, with scattered, cosmic dust. So near, now, belting monster Saturn. So calm, so grand, so unutterably beautiful. But deadly.

"A trillion-trillion little moons," Anna said softly, all traces of any resentment she may have felt for Ron Leiccsen gone now. "Or many more, even, than a trillion-trillion. Hurtling around Saturn in a sort of stream at a velocity of many miles per second. Most of them dust, as fine as powder. Steer the Barbarian into the Rings, Ronnie. Instantly those countless, tiny meteors will riddle our ship—and us."

For just a second Ron Leiccsen stared at that awful, dazing spectacle. It made his throat ache with awe. There was a fascination about the Rings, something unholy that beckoned suicide. But then Ron laughed, as though he was part of that miracle—a man about to use the tools of the deities for his own purposes. Two things he remembered, especially. That the Barbarian was moving very fast. And that it was to the right of Saturn, considering the northern hemisphere as upward.

"Thanks, Anna," he said cryptically, as more projectiles from the rapidly nearing Callistan ships blazed close to them. "Hold tight to your stanchion, because here goes! And don't blame me if you're surprised at what happens!"

For a moment he adjusted the velocity dials carefully. The Barbarian slowed a little, then swerved, nosing at a gradual slant toward the glory of Saturn's Rings. No inferno could have held a magnificence like this! A stupendous, murky, curving ribbon, like an inconceivable circle-saw, rotating at meteoric speed! So, certain death seemed to hurtle closer. A matter of mere instants, now....

In a second, the plunge was completed. Within the Barbarian's hull, a dazing din roared suddenly. Partly like a magnified hailstorm, beating on a sheet-metal roof. Myriads of dust-grains, and tiny pebbles of meteoric iron and rock, were colliding with the freighter's hull. It seemed impossible that any ordinary meteor-armor could turn aside such an avalanche. Even Ron Leiccsen wondered that they were still alive, and that their bodies, and the steel shell of their ship were still unriddled, before he remembered why.

The murk of cosmic powder swallowed them, until the Callistan battle-craft, and the stars themselves, were lost to view. Ahead, through the observation bay, only a yellowish, foggy light showed—sunshine penetrating deep into the hurtling substance of the Rings. Uncountable billions of minute particles, whirling in eternal moon-paths around the gigantic if tenuous mass of Saturn.

"They can't shoot at us now," Anna shouted, straining her voice so that it might be heard above the hail-like clamor, and the gigantic hissing, soughing sound—like blowing sand—that dinned within the vessel. "They can't even see to shoot at us, through all this dust! And even if they dared follow us, they couldn't find us! But how can it be, Ron? All these meteors are traveling at planetary velocities—maybe twenty or thirty miles a second! Small as most of them are, they should still tear through the steel armor of the Barbarian, as though it was butter! How is it that we're still alive?"

Ron was conscious of the bigness of the question, and yet the simplicity of the answer now.

"Nothing to it!" he shouted back. "We approached Saturn from the right. It rotates in the same direction as does the Earth—to the right, if you consider that down lies toward the southern hemisphere, and that up, of course, lies toward the northern. So do the Rings. With but one exception, the direction of rotation is the same everywhere, for all the bodies in the solar system. And now space ships equal and exceed the velocities of planets and meteors. The Barbarian was moving at many miles per second, too, paralleling the Rings, and going the same way. I adjusted our velocity a little, so that the difference between it, and that of the Rings, is very small. Relativity, Anna. And now that we've plunged into Saturn's cosmic belts, the difference in speed gives the meteors only enough relative momentum to make a lot of noise, when they strike our ship. They can't puncture us."

Anna Charles gasped as she realized the easy truth. "Then we can go all around Saturn hidden in the Rings!" she burst out enthusiastically. "Even though we can't see much, we can fly blind with our instruments. But—" and her hopeful expression became faintly worried again—"we've got to emerge into free, clear space sometime! To cross out to Titan! And there the Callistan ships will spot us. They'll have plenty of time to blow us up!"

Ron Leiccsen chuckled under his breath. It was funny to hear reckless, daring Anna Charles talk like this now, while he, the cautious, careful planner, felt a wave of contrasting optimism. Maybe they'd both learned something from each other.

"Wait and see, Anna!" he yelled back. "You might be surprised again! Remember, I'm a machinist!" On his lips was a taunting smile of confidence.

Hours later, having circled Saturn, they dipped out of the Rings. But as the murk that had concealed them cleared, and the voidal stars showed bright again, they found a group of Callistan battle-craft not much more than a hundred miles away, their burnished hulls gleaming silvery in the faint sunshine.

"Ron!" Anna quavered, with a nervous catch in her voice. "We'll never make it, now! They'll surely destroy us!"

Young Leiccsen gripped the controls, and put on full speed. His face was grim, but that crooked smile was there again, tracing a line in his left cheek.

"That, Anna," he said, "remains to be seen."

Through her telescope, the girl continued to watch the enemy vessels, gleaming like silver arrows against the hard blackness of space. It was impossible that the keen-eyed lookouts aboard those warships did not see the black Earth-craft. And yet they approached no nearer. Their atom guns did not fire. The Barbarian was continuing on out toward Titan, quite unmolested.

Anna Charles' beautiful face was alight with puzzled wonder again. "Maybe I'm dumb, Ron," she murmured. "Just like I was last time. But I still don't understand why the Acharians neglect such a splendid chance to finish us."

Ron pointed toward a heavily glazed side-port in the control-turret. "Look out there," he suggested. "Back at our own hull."

Half rising from the pilot-seat, he was looking, too. They couldn't see much of their ship's flanks from the little window, but what they could see of its great, spreading guide-fins was plenty.

Those guide-fins had been deeply black, once. Now they were almost as bright and shiny as a polished mirror.

"When we were in the Rings," Ron explained, "all those fine meteors pounding against the Barbarian rubbed off every last speck of her black lacquer, and gave the metal underneath a swell polish, besides! I knew that it had to happen, of course. It was just a very ancient machinist's trick, with a new, cosmic wrinkle. In effect, this old tub of ours was just sand-blasted, Anna."

"Why, certainly!" the girl exclaimed in pleased startlement. "I should have guessed it, too! The Barbarian is bright silver now, instead of black! From a distance the Callistans think it's one of their own silvery ships! And so, naturally, they don't bother us!"

"Uhuh," Ron chuckled. "So far, so good! Now maybe we can concentrate on delivering our mysterious cargo, as per Arne Reynaud's instructions. It's all up to him, now! We're going to find out whether he was crazy, or, to put it mildly, truly clever!"

Disguised as it was, the Barbarian reached Titan's far upper atmosphere without trouble. Evidence of fighting could be seen, many miles beneath. Puffs of explosions in the weak sunshine. Silver ships flying, spreading final destruction over the richest farm country in the solar system—richest because of those scattered sun-ray towers and their secondary, plant-stimulating radiations, and the fact that Bart Mallory, the inventor, permitted the patent rights to be used only for the Leiccsenland Colony.

A few of those towers were shattered, now; but most of them still shed their sunlike brilliance. The Callistans needed them, if conquest was completed, to maintain the warm climate and the fertility of the farms. So, in general, they had avoided their destruction. And when, as now, the sun itself shone during the day, it was useless for the Earthians to shut off the globes for blackout protection.

The dread Callistan ships were coming over again, death spewing from their silver bellies.

"Our people are still battling!" Anna said happily. "For weeks, with all radio-communication blocked off by the Callistan static-barrage, we didn't even know that, for sure! But it's a good sign!"

"Maybe," Ron commented with a shrug. "Anyhow we're here high up in the atmosphere. Arne Reynaud said 'Scatter the cargo.' That should be easy to do from this position. So, here's how!"

He pulled a lever which had been an enigma to Anna and to himself through all their return voyage from Mars. It was the lever which opened the discharge-vent of the Barbarian's hold.

Peering wonderingly from the side-ports of the control-room, the man and the girl saw what was coming out of that discharge-vent, and settling gradually toward Leiccsenland, and the surrounding hills, far beneath.

A brownish cloud—like chaff—that was all. It swirled astern like a streamer, in that high, frigid altitude. It scattered, so that it dissolved from view. Spreading, sinking downward.

"Not very impressive, is it?" Anna asked anxiously. It was plain that she was doubting Arne Reynaud's mysterious weapon more and more. Just chaff. What could it ever do against the Acharians, armed to the teeth, hardy, and prepared for all violence?

"Not very impressive," Ron agreed with a cynical shrug.

But he kept guiding the freighter around and around at that vast altitude until the discharge-spout had ceased to trail brown, chaffy dust. The hold was empty. The job, at least, was accomplished, now, according to exact specifications.

Not two minutes after it was completed, a shell exploded before the prow of the old freighter—a signal to halt. Many burnished Callistan war-craft were approaching.

As Ron cut the power in the propelling gravity plates astern, he looked at Anna. "Well," he drawled, "I guess this is where we stop being free Earthians."

The girl nodded, biting her lip.

Ron switched on the short-wave radio, which, over a limited distance, could function, in spite of the static barrage. Over it came harsh Callistan tones:

"You are blockade runner, perhaps. It is old trick—making ship shiny, like ours. But from very close, we recognize Earthly shape of your hull. Terrestrial resistance on Titan almost finished. Please land outside Leiccsendale."

With so many weapons trained on the unarmed Barbarian, there was little to do but obey orders. Ron guided the ship groundward. But as it came to rest on the charred soil of what had once been an orchard, he turned a control dial on which there were red marks—danger graduations, indicating the limiting point of safety. He turned the dial well past those points. The engines of the ship howled and groaned with a fearful overload for a moment. Then there was a dull, grinding, ripping noise astern, and the crackle and hiss of fire.

When the two Earthians emerged, red flames and black smoke were rising from the crumpled aft-portion of the vessel. The engines had been immersed in vats of oil to insulate their power. And now that oil was blazing. The Barbarian at least would be useless to the enemy, and the secret of its cargo, whether a dangerous secret or not, would be hidden in the ashes and the ruins.

But for Anna Charles and Ron Leiccsen, this was the beginning of slavery. Within a hundred hours of their capture, Callistan heat-rays and shells and heat-bombs had put down the last resistance of the terrestrial colonists. They were all either chattels or dead—those who had not left Titan in time. The colony had possessed enough ships to remove everyone to Earth; but those that had not been used had fallen into Acharian hands.

The captives were herded into their barracks—the few half-ruined farm-buildings which still stood, after the conflict was over. They were put to work repairing damaged sun-towers, re-cultivating desolated fields, and helping the Callistan engineers erect the burnished metal structures which duplicated in architecture the buildings of that distant moon of Jupiter. Rapidly, Mado Achar—New Callisto—was being born. Bizarre cactiform vegetation, from the flowerless mother-world, began to sprout from spores, under the stimulus of the radiations from Bart Mallory's sun-ray towers.

And among the chattels, the whip was not spared. Frequently a slave, driven to vengeful mania by maltreatment and overwork, was blasted down with a heat pistol, by some furry, laughing overseer.

Ron Leiccsen saw Anna Charles only rarely, at assembly roll-call periods. Always she looked tired from endless hours in the fields. Still sweet and beautiful, though, even through the grime that covered her face and tattered clothing. Luckily Callistans were not attracted to Earth-women.

Once Ron got a chance to talk with her for a few minutes, in the shadow of a fire-charred warehouse.

"I can't stand it much longer, Ron," she whispered raggedly, her face strained with horror. "At the end of the last work-period, I saw Joe Kerrin killed, his head and shoulders burned off with a heat pistol, simply because he was too weak to carry a heavy box of tools. Kerrin was an old man, Ron, and a neighbor of mine. And that isn't all! Not long ago, Ollie Marvick, only eleven years old, was kicked to death by one of the overseers, because he was too ill to work. Ollie was a student of mine at school, and one of the few kids that wasn't gotten out of Titan in time. I tell you I can't endure it, Ron! I'll go crazy! So—well—some of us have been thinking of making a break for the hills."

The hills! Ron Leiccsen had seen horror, too; horror that there was no way to fight, downtrodden and disarmed as the Earthians here now were. The hills that rimmed Leiccsenland—the borderline region between the reclaimed territory, warmed by the sun-ray towers, and the still bleakly frigid portion of Titan, as yet uncolonized. Ron's mind ached with a fierce, sharp eagerness at the thought of the hills, and all the wild, self-reliant pioneer blood in him throbbed violently. It was natural for beautiful, reckless Anna Charles to be forced toward the idea of escape.

But then Ron looked toward those hills, and at the intervening rows of silvery Acharian ships resting on the ground. A barrier that stood in the way! And there were many furry guards pacing, too, their accoutrements and gaunt, deadly weapons glinting in the glare of the sun-ray globes.

Ron saw how hopeless it all was. It was all but impossible to get past those guards, and those heavily armed vessels. And even if you did get to the hills, what then? Doubtless even now they were the refuge of many colonists who had fled Leiccsenland before the final surrender. But sooner or later they would all be tracked down by burnished, vulture-like ships, flying overhead.

Ron's common-sense conquered. "Don't try to break away, Anna darling," he urged seriously. "At least not yet. You see, it's almost sure death. Remember we're still relying a little on Arne Reynaud's plan, which we carried out. Maybe it's one of those schemes that takes time to develop."

Even as he spoke, the usually cynical young machinist was aware that he was not talking much like himself. Once he'd denounced Arne Reynaud. But then things had been different. Retreat to Earth, in favor of which he had argued, had still been possible for everybody, then. Now all those who had remained behind were prisoners, and you had to make the best of a bad situation. You had to find hope where you could, even if its basis was only the word of a dreamy old horticulturist.

He was relieved to see Anna nod agreement before she left him. "Okay, Ron," she whispered. "I'll try to endure it." Her dark eyes were misty and strange, as she continued: "And I'll say 'darling,' too, because I think you meant it as I do. Maybe you're right. I guess we should wait, before we try to escape to the hills. But I've sort of lost faith in Arne Reynaud."

Ron kissed Anna then, and let her walk away toward one of the women's barracks. But all the time he was thinking of her words—lost faith. And what a tragic let-down it would be, if Arne Reynaud's scheme proved fruitless. That daring race across the void to Mars, to bring in the Barbarian and its unknown cargo. The eluding of the Callistan ships by facing death in a dive into the incredible grandeur of Saturn's Rings. The sand-blasting by those tiny meteors, changing the freighter's black-painted hull, the obvious mark of a terrestrial ship, to a polished, gleaming, Acharian disguise! These things were all triumphs in themselves. But if Arne Reynaud's brown, chaffy dust, sprinkled over Titan's surface, failed to turn Callistan conquest into defeat, then all this luck and effort was for nothing!

Then the Titan Colony might just as well not have been established! The frozen atmosphere and water of the far-flung world might just as well never have been thawed! The building of the sun-ray towers had been futile, then. Anna Charles and he, Ron Leiccsen, might just as well never have met and quarreled and fallen in love! For Acharians, with their gray fur and beady eyes, and harsh, mocking, inhuman laughter, would rule forever here then, and their human slaves would be worked until the last of them had dropped, or had been destroyed.

So, in increasing bitterness, time passed for Ron Leiccsen, in spite of his will to be patient. It was daylight, always, of course, with the sun-globes glowing eternally, just as they had in the old days, before the conquest. The tiny sun itself would creep slowly across the sky, and set, as Titan revolved around Saturn. A great, long day, like the day of Earth's moon; for, like the latter, Titan rotated only once on its axis, every time it completed a journey around its parent planet. But all this made no difference. There was no night—only the brief sleep-periods in the ever lasting light of the Mallory towers.

Ron was transferred from the construction of Callistan apartment houses, to a job in a newly completed factory. There, under a cruel, petty old tyrant in dirty fur, Ron toiled in a little cell, polishing metal plates. Acharians loved burnished surfaces.

Young Leiccsen could talk with no one now, except his boss, Arruj. For he was forced to sleep at the foot of his polishing machine. And he ate the food brought to him while the abrasive discs whirled. He had only this little metal cubicle to live in now, with its heavy door locked, its single window barred.

"Be faster, Eart'man!" Arruj would growl. "Or shall I beat you more. Maybe I kill you, this moment, eh." And then Arruj would laugh uproariously, and seem to wait for an outburst or an attempted assault that would give him an excuse. Ron could hear the breath wheezing and whistling in the Acharian's great chest.

It took all the courage, and all the will that Ron Leiccsen could muster, to check that maddening impulse of murder. But always, so far, he had controlled himself, because he still clung savagely to hope. But it was still there, maybe only because he willed its presence.

Arruj wasn't in the room most of the time, for there were other slaves to supervise in other cubicles in this great factory building. When Arruj was gone, there was always a chance to climb up on a bench for a moment, and look out of the barred window.

The building of the Callistan city was continuing, strange, square, shiny structures rearing bizarrely among the half-ruined houses of Leiccsendale. The construction work took first place, of course, ahead of the replanting of the desolated land. But strange, flat-leaved, flowerless growths from Callisto, were already sprouting before those gleaming new factories and dwellings.

The distant hills, which seemed forever unreachable now to Ron in his prison, showed a faint, unfathomable green now, even at their pinnacles. Young Leiccsen often wondered about this, for the higher slopes of the hills had been barren before of vegetation. The twenty-three years since Leiccsenland had been thawed, and Earthians had come to Titan, had been insufficient time for much of the imported plant-life to spread to the rocky crests.

During his stolen moments of observation, Ron watched other human slaves, toiling in some of the fields, clearing away fire-charred corn and other Earthly crops, to plant Acharian spores. But most of the cultivated land was still neglected by the conquerors. It showed that same rough green as the far-off hillsides. Weeds, it looked like. And yet no weeds had ever been brought to Leiccsenland, as far as Ron knew. The colonists had always been careful to see that the imported seed was pure.

Vaguely, Ron wondered if these growths were something from Titan's tremendously ancient past, when Saturn had been a hot, youthful world, acting as a warming sun to its satellites. Some vestige of plant-life preserved here through the frozen eons. But why should such vegetation appear suddenly, now? Why hadn't its seeds sprouted as soon as Leiccsenland had been thawed, years ago, if they had existed?

And then, with a sudden inspiration, Ron saw part of the truth. The brown, dusty stuff that had filled the hold of the Barbarian! Seed of some kind! Arne Reynaud's plan! But what in the name of sense could it all be about? Those growths out there weren't poison, evidently! Ron saw both Callistans and Earthians handle them with impunity! What harm could they ever be to the invaders?

None! With a cold wave of despair, Ron reached this inevitable conclusion. So this, then, was the final disillusionment! Reynaud had been a crackpot after all! Like many a hare-brained inventor, he had dreamed only nonsense! And the struggle to carry out his wild scheme had been utterly wasted!

Ron Leiccsen sank into black dejection. Once, beyond the wall of the great factory, he heard a flurry of hisses. Heat-guns and pistols being discharged. And then human screams of agony—and silence.

Stealing another moment to peer from the window, he saw furry guards reloading their weapons, after the brief, murderous action. On the ground, too far off for their personal identity to be revealed, were burnt and crumpled human corpses. A group of colonists, maddened by their heartless overlords, must have tried to escape to the hills. And this was their end.

Had Anna Charles been among them? Quite possibly. Reckless and brave and impatient as she was, it was almost probable. And Ron Leiccsen couldn't have found it in his heart to blame her. He would have been among that bunch of rebels, too, if he hadn't been imprisoned here. Grief struck home, until his eyes misted and his throat ached.

Arruj came into his cubicle not long afterward. "Very little more time for you to live, Eart'man," he announced gleefully. "When our city built, we kill all Eart'folk. No good! Much trouble! Always try revolt! All things from Eart' no good! Except sun-ray towers. Plants from Eart' no good! Don't like Eart' plants. Corn, grain, trees, everyt'ing! Look ugly. No use. We root up—destroy!"

Arruj emphasized his hatred of all that was terrestrial by striking Ron across the back with his metal staff. Blood oozed, dying the filthy tatters of Ron's shirt.

But the young machinist remained quite cool. He wouldn't have to curb that lust for murder much longer! There was a certain guide-bar that was part of his polishing machine. It could be unscrewed without much trouble. Next time Arruj came into his cell, he would strike him down, before the Callistan could reach the pistol in his belt. He would kill Arruj at least—smash his hideous, fur-draped head, and have the satisfaction of seeing the petty tyrant's bloody brains dribble, before the other Acharians killed him, too. Partial revenge! Ron knew now that there was no need to conserve his own life. For hope was gone.

This time Arruj stayed for quite a while in Ron's cubicle, as he inspected the machine, and the quality of the work his chattel was turning out.

"Very, very bad!" he grumbled, commenting on the latter without sound reason except plain cussedness. "Vaah! It will be great pleasure to see you die, Eart'man! You are even more useless than the others."

Ron scarcely listened. He was too used to this treatment by now. He turned his face upward toward the window, toward blue sky and brilliant artificial daylight. It was like an afternoon in late summer, on Earth.

Suddenly a swift gust of breeze began to blow from across the fields and from the distant hills. It was refreshing and cool to Ron, as it filled his stuffy cell.

"Your work is very, very bad, Eart'man," Arruj repeated. "I beat you more now!"

He raised his staff to strike. But then, half-way up, the end of the metal rod wavered. Arruj drew in a great, spasmodic breath. An instant later the wind in his vast lungs was expelled in a mighty sneeze!

Once more he inhaled deeply and spasmodically, and again an explosive sneeze tore through his wide-flairing nostrils. But this was only the beginning. Rapidly the sudden fit that had gripped him grew worse, as sneeze was heaped on sneeze in agonizing, choking succession.

Wonderingly Ron turned to watch. Arruj's pink skin, showing here and there through his fur, had turned livid. He was strangling. His little eyes were streaming tears so profusely that he could not open them. His strange, three-fingered hands clutched at his chest as though he had inhaled a whiff of lethal gas! He tried to speak, but he could not. His strangled, bellowing, tortured lungs would not give him time, as one coughing, sneezing explosion came after another, in a swift, inexorable sequence.

He tried to grope for his keys, to unfasten the locked door of the cell and reach the open air. But the effort was lost in a confused, quaking gesture. He could not keep his hands steady for a second, as the violent spasm that heaved and tore at his breathing organs, fairly threw his whole body off balance! The keys jingled to the floor, and he tried to find them, feeling with his fingers. His streaming eyes were blinded, so that he could not see. Weakened and choked, he crumpled to his knees, and sprawled helplessly on his belly. But that smothering, drowning fit that wracked him, went on.

From this point, the transition from humor to horror was swift. Bloody froth came to Arruj's lips. He writhed. His sneezes and coughs and raking gasps became less forceful with exhaustion, but more hideous, with the bubbling, scratching sound of an unmistakable death-rattle.

All this, Ron Leiccsen watched, almost without moving. He was too fascinated, too puzzled, too unbelieving to move. But then, as if remembering a duty, he picked up Arruj's staff. It was quite massive. He lifted it, and aimed a blow at Arruj's skull. But the blow that would have pulped the Callistan overseer's gray matter, never was delivered. Ron felt suddenly sheepish—almost guilty. It was against best human principle to murder a helpless enemy. And Ron did not need the word of a physician to know that Arruj was dying.

But how? Why? That was the question! Ron listened. Dimly, within the great, roaring factory, and beyond its walls he could hear more coughs and sneezes, like the rattle of great drums. No human chests of Earth could have produced such noises. Only the great barrel-like thoraxes of Callistans could ever reverberate like that!

It was a plague, then. Something that must have stricken them all, suddenly. But how was it possible? They were tough, these beings from that moon of Jupiter. Earth-germs, for instance, did them no harm. And there were few native Acharian diseases that their rugged flesh could not throw off. Still, now, there was a pestilence among them—a killing horror, swift and strangling! Ron Leiccsen thought of Arne Reynaud, and wondered.

Then he saw the keys there on the floor, beside Arruj's writhing, tortured form. He picked them up, chose the one he knew fitted the lock of his cubicle, and opened the door.

Cautiously he stepped over the quivering, doomed Arruj. In the corridor outside, along the row of cells, other Callistans sprawled, helpless and strangled, their efforts to breathe consisting only of horrible, gurgling gasps. Something must be swiftly inflaming their lungs, until death by strangulation was inevitable. Like pneumonia or diphtheria, but far more rapid.

In a daze of wonder, in which hope and optimism scarcely dared to rise, Ron rushed from one cubicle door to another. It was easy to release the human slaves who had worked the machines within each cell. All the doors could be unlocked with the same key as his own.

Startled, unbelieving men collected in the corridor, as he freed them. Men with great welts from many beatings on their backs, and dull gleams of confusion in their eyes. Larsen, Schneider, Novak, Lloyde, and a host of others.

Bart Mallory, the inventor and patent-holder of the sun-ray towers, was there, too, his once neat beard, which had been clipped in a Van Dyke fashion, an unkempt tangle, now.

"What's happened, Leiccsen?" he croaked. "We're free! I don't understand! How can all the Callistans be suddenly ill like this—dying?"

"I don't know," Ron stammered. "We'll have to try to find out."

Like a bewildered pack the liberated slaves rushed to the factory exit. There, on the metal steps, a half dozen Acharian guards lay helpless. One already had ceased to sneeze and strangle. The dark red froth on his lips had ceased to drip to his bosom, smearing his fur. He was already dead.

Before the factory exit, the released prisoners halted, staring across the plain, brilliant in the glow of the sun-towers. Leiccsenland still looked beautiful, though weird with the addition of strange, gleaming Acharian buildings, and with a puzzling greenness that had sprouted from the charred ground, masking the effects of Callistan vandalism, not so long ago. The conqueror-fleet of silvery ships stood in serried rows of silent power at the edge of a fire-blackened woods, that was beginning to show new leaves, once more.

But not one of the invaders, among the hundreds that could be seen, stood on his feet. All writhed on the ground, in the streets, on the lawns, and beside the ships, helpless. The stamp of doom was upon them—sudden, subtle, nameless destruction!

Then one of the Earthmen sneezed. Smith, it was. He was a big, husky fellow; but now his red cheeks blanched with fear. His unpleasant thought was easy to understand. That sneeze looked like a symptom. Were the Earthians, the colonists, to be wiped out by this hellish plague, too?

Ron looked at Bart Mallory, and Bart Mallory stared back in concerned doubt. A group of other slaves who had been clearing the unkempt fields, were coming forward, shouting questions. Ron saw Anna Charles among them, haggard and tattered, but still alive, still herself. Impulsively he ran swiftly toward her.

"Anna—honey!" he blurted, as he gathered her briefly into his arms. "You didn't try to break away to the hills. They didn't kill you! But now—I don't know what to think. This is Arne Reynaud's scheme come to fruition, isn't it? But maybe it'll get us, too—this pestilence."

He looked at her carefully. With increasing worry, he saw that her nose was red. Her long eyelashes were blinking back telltale moisture. And yet it didn't seem as though she'd been crying or anything. Were these, then, more forerunners of the plague? Several other men sneezed violently. And Ron looked, with a touch of real fear, at the motionless body of a Callistan, lying on the grass nearby, its fur blowing in the wind. Maybe the Acharian doom was also going to be an Earthian doom.

"Anna—" Ron gasped. That single name, as he uttered it now, was like some strange plea and prayer to the unknown.

But the girl smiled back at him. "I think that I'm the one who understands what this is all about this time, instead of you, Ron," she declared almost tauntingly.

"Then tell us, Miss!" Bart Mallory urged in a half-frantic tone.

Anna glanced briefly and mysteriously at the bulk of Saturn—a pale, pearly, enhaloed bubble at the horizon—above the now green-tinted hills.

"Yes, it's Arne's scheme come true," she said musingly. "The Acharians lived unknowingly with death here, for almost two terrestrial months. Too few of them had ever visited Earth, even to recognize the enemies that lurked there for them. And when that nemesis was brought here, it was far too harmless and unobtrusive in its aspect, for them to notice or be warned.

"Remember what Arne Reynaud told us, long ago, just before he was killed by one of those Callistan heat-guns, in front of the Leiccsendale Community Bank? The time he made his speech, Ron? You heard him, too, Mr. Mallory. I think I can quote almost his exact words:

"'Me and a brother of mine are probably the only men, Earthian or Callistan, who realize why Callistans get very sick on Earth at certain times—though it's simple.... I saw one die once, there, in summer. It ain't just the density of the air. They can stand that. Something else. I found out...."

"Well, what is it, then?" Mallory demanded, not meaning to sound impatient.

The girl glanced at him, then back at Ron, then all around at the waiting faces. "We all know, don't we," she said, "that we are used to certain conditions, we Terrestrials from Earth. We get tough and acclimated. People from other worlds, not used to similar conditions, wouldn't have the same resistance. Space travel bears this out—Martian plagues spreading on Earth—Venusians dying of the common cold. Even an interchange of germs between the terrestrial continents was dangerous, according to history. Tuberculosis ravaging the American Indians. Eskimoes killed by the measles. Terrestrial germ diseases don't bother the Callistans, it is true, because their blood is at too high a temperature for Earthly bacteria to survive. But there's another thing—a weak point. The cargo Ron and I brought from Mars in the Barbarian, was the answer."

"Then you guessed, too, what that cargo was, Anna," Ron burst out. "Seeds of some kind—plants. They're growing elsewhere now. Out there in the fields, and on the hillsides. But that's all so crazy! Where can there be any danger in simple, everyday Earth-weeds? Poison ivy is bad, of course; but even it couldn't kill off thousands of Callistans—certainly not in a few minutes!"

"Yes, I guessed what the Barbarian's cargo consisted of, Ron," Anna returned. "I was working in the fields all the time, seeing those plants, which had never been on Titan before. Not even many of the slaves remembered them, though, since we've all been a long time away from home, and from some of the familiar things, there. But I'm a school teacher, and I know a little about biology, and the common afflictions of humankind. But I kept still, because secrecy might be important. Well, those plants grew like wild-fire, under the stimulating rays of the sun-towers. And I was praying that they'd hurry up and blossom. Callisto's a flowerless world, Ron. Probably that's the big point. With an equal start in their growing, the plants blossomed all at once. And the winds blew, and the plague came. And now we colonists are masters of Titan once more. The Acharians can never threaten us again. Not even if they find a way to face the pestilence with filter-masks and so forth. For we've got the major part of their space fleet to protect us. Do you know what I'm talking about now, Ron? Everybody?"

There was an awed quiet in the listening crowd. Then Bart Mallory whooped suddenly. "I get it!" he shouted in triumph. "Of course! Callistan lungs are huge and delicate and entirely unacclimated to one Earthly condition! Naturally they'd react to it far more violently even than we do! And now Terra is mistress of this section of space! My sun-towers must have helped some, by increasing the normal virulence of the plants. But most of the thanks go to Arne Reynaud, and to you, Anna, and to you, Ron."

Mallory, the scientist, swept his arms out toward the fields. Waving there in the bright artificial sunshine, was a tattery green host of plants, that men of Earth had known and lived with, with considerable discomfort but scant real harm for countless ages.

Was it just the wind that blew that host, making it sway and undulate with a simple grandeur, while huge Saturn looked on? Or was the unseen spirit of Arne Reynaud, the old horticulturist, the old fool, the dreamer and the wizzard, stirring them, too?

Ron Leiccsen scowled, still lost and bogged down with the enigma, as were most of the other listeners. "I guess you've got to draw me a diagram, Anna," he grumbled, shaking his head ruefully. "I know a lot about machinery and space ships and Saturn's Rings, but it looks as though this biological problem goes beyond my depth."

Anna Charles smiled a faint, twisted little smile. "We've been through a lot together, Ronnie," she said wistfully, not caring if the others heard. "We've quarreled a lot, learned an awful lot together, and I think at last found that life could be beautiful for us both. So I can afford to be patient. Now look—"

She bent down. Her little fists clutched a tall, tattery plant, that grew nearby in the grass. Tugging vigorously, she pulled it out. From its top, where there was a cluster of homely golden nodules, there dusted a fine, yellowish powder. Pollen.

Anna's nose wrinkled. Suddenly she sneezed very hard.

"Somebody ought to write some music about this plant, now," she said at last. "It is commonly known as—Ragweed. Some Terrestrials are terribly alergic to it, though nothing like the poor Acharians from flowerless Achar, of course. Its dry pollen, drifting with the summer breeze, causes more—and more violent—hay-fever, than anything else known on Earth!"