He reached the caves at night. No one was up but George Ord, working late in his combination workshop-laboratory.

George looked up at the sound of his entrance and saw that he was alone. "So Dan didn't make it?" he asked.

"The chasm got him," he answered. And then, wearily, "The chasm-we found the d.a.m.ned thing."

"The red stratum-"

"It was only iron stains."

"I made a little pilot smelter while you were gone," George said. "I was hoping the red stratum would be ore. The other prospecting parties-none of them found anything."

"We'll try again next spring," he said. "We'll find it somewhere, no matter how long it takes."

"Our time may not be so long. The observations show the sun to be farther south than ever."

"Then we'll make double use of the time we do have. We'll cut the hunting parties to the limit and send out more prospecting parties. We're going to have a ship to meet the Gerns again."

"Sometimes," George said, his black eyes studying him thoughtfully, "I think that's all you live for, Bill: for the day when you can kill Gerns."

George said it as a statement of a fact, without censure, but Humbolt could not keep an edge of harshness out of his voice as he answered: "For as long as I'm leader that's all we're all going to live for."

He followed the game south that fall, taking with him Bob Craig and young Anders.

Hundreds of miles south of the caves they came to the lowlands; a land of much water and vegetation and vast herds of unicorns and woods goats. It was an exceedingly dangerous country, due to the concentration of unicorns and prowlers, and only the automatic crossbows combined with never ceasing vigilance enabled them to survive.

There they saw the crawlers; hideous things that crawled on multiple legs like three- ton centipedes, their mouths set with six mandibles and dripping a stinking saliva. The bite of a crawler was poisonous, instantly paralyzing even to a unicorn, though not instantly killing them. The crawlers ate their victims at once, however, ripping the helpless and still living flesh from its bones.

Although the unicorns feared the crawlers, the prowlers hated them with a fanatical intensity and made use of their superior quickness to kill every crawler they found; ripping at the crawler until the crawler, in an insanity of rage, bit itself and died of its own poison. They had taken one of the powerful longbows with them, in addition to their crossbows, and they killed a crawler with it one day. As they did so a band of twenty prowlers came suddenly upon them.

Twenty prowlers, with the advantage of surprise at short range, could have slaughtered them. Instead, the prowlers continued on their way without as much as a challenging snarl.

"Now why," Bob Craig wondered, "did they do that?"

"They saw we had just killed a crawler," Humbolt said. "The crawlers are their enemies and I guess letting us live was their way of showing appreciation."

Their further explorations of the lowlands revealed no minerals-nothing but alluvial material of unknown depth-and there was no reason to stay longer except that return to the caves was impossible until spring came. They built attack-proof shelters in the trees and settled down to wait out the winter.

They started north with the first wave of woods goats, nothing but lack of success to show for their months of time and effort.

When they were almost to the caves they came to the barren valley where the Gerns had herded the Rejects out of the cruisers and to the place where the stockade had been. It was a lonely place, the stockade walls fallen and scattered and the graves of Humbolt's mother and all the others long since obliterated by the hooves of the unicorn legions.

Bitter memories were reawakened, tinged by the years with nostalgia, and the stockade was far behind them before the dark mood left him.

The orange corn was planted that spring and the number of prospecting parties was doubled.

The corn sprouted, grew feebly, and died before maturity. The prospecting parties returned one by one, each to report no success. He decided, that fall, that time was too precious to waste-they would have to use the alternate plan he had spoken of.

He went to George Ord and asked him if it would be possible to build a hypers.p.a.ce transmitter with the materials they had.

"It's the one way we could have a chance to leave here without a ship of our own," he said. "By luring a Gern cruiser here and then taking it away from them."

George shook his head. "A hypers.p.a.ce transmitter might be built, given enough years of time. But it would be useless without power. It would take a generator of such size that we'd have to melt down every gun, knife, axe, every piece of steel and iron we have. And then we'd be five hundred pounds short. On top of that, we'd have to have at least three hundred pounds more of copper for additional wire."

"I didn't realize it would take such a large generator," he said after a silence. "I was sure we could have a transmitter."

"Get me the metal and we can," George said. He sighed restlessly and there was almost hatred in his eyes as he looked at the inclosing walls of the cave. "You're not the only one who would like to leave our prison. Get me eight hundred pounds of copper and iron and I'll make the transmitter, some way."

Eight hundred pounds of metal . . . On Ragnarok that was like asking for the sun.

The years went by and each year there was the same determined effort, the same lack of success. And each year the suns were farther south, marking the coming of the end of any efforts other than the one to survive.

In the year thirty when fall came earlier than ever before, he was forced to admit to himself the bleak and bitter fact: he and the others were not of the generation that would escape from Ragnarok. They were Earth-born-they were not adapted to Ragnarok and could not scour a world of 1.5 gravity for metals that might not exist.

And vengeance was a luxury he could not have.

A question grew in his mind where there had been only his hatred for the Gerns before. What would become of the future generations on Ragnarok?

With the question a scene from his childhood kept coming back to him; a late summer evening in the first year on Ragnarok and Julia sitting beside him in the warm starlight . .

"You're my son, Billy," she had said. "The first I ever had. Now, before so very long, maybe I'll have another one."

Hesitantly, not wanting to believe, he had asked, "What some of them said about how you might die then-it won't really happen, will it, Julia?"

"It . . . might." Then her arm had gone around him and she had said, "If I do I'll leave in my place a life that's more important than mine ever was.

"Remember me, Billy, and this evening, and what I said to you, if you should ever be leader. Remember that it's only through the children that we can ever survive and whip this world. Protect them while they're small and helpless and teach them to fight and be afraid of nothing when they're a little older. Never, never let them forget how they came to be on Ragnarok. Someday, even if it's a hundred years from now, the Gerns will come again and they must be ready to fight, for their freedom and for their lives."

He had been too young then to understand how truly she had spoken and when he was old enough his hatred for the Gerns had blinded him to everything but his own desires.

Now, he could see . . .

The children of each generation would be better adapted to Ragnarok and full adaptation would eventually come. But all the generations of the future would be potential slaves of the Gern Empire, free only so long as they remained unnoticed.

It was inconceivable that the Gerns should never pa.s.s by Ragnarok through all time to come. And when they finally came the slow, uneventful progression of decades and centuries might have brought a false sense of security to the people of Ragnarok, might have turned the stories of what the Gerns did to the Rejects into legends and then into myths that no one any longer believed.

The Gerns would have to be brought to Ragnarok before that could happen.

He went to George Ord again and said: "There's one kind of transmitter we could make a generator for-a plain normal-s.p.a.ce transmitter, dot-dash, without a receiver."

George laid down the diamond cutting wheel he had been working on.

"It would take two hundred years for the signal to get to Athena at the speed of light,"

he said. "Then, forty days after it got there, a Gern cruiser would come h.e.l.l-bent to investigate."

"I want the ones of the future to know that the Gerns will be here no later than two hundred years from now. And with always the chance that a Gern cruiser in s.p.a.ce might pick up the signal at any time before then."

"I see," George said. "The sword of Damocles hanging over their heads, to make them remember."

"You know what would happen to them if they ever forgot. You're as old as I am- you know what the Gerns did to us."

"I'm older than you are," George said. "I was nine when the Gerns left us here. They kept my father and mother and my sister was only three. I tried to keep her warm by holding her but the h.e.l.l Fever got her that first night. She was too young to understand why I couldn't help her more . . ."

Hatred burned in his eyes at the memory, like some fire that had been banked but had never died. "Yes, I remember the Gerns and what they did. I wouldn't want it to have to happen to others-the transmitter will be made so that it won't."

The guns were melted down, together with other items of iron and steel, to make the castings for the generator. Ceramic pipes were made to carry water from the spring to a waterwheel. The long, slow job of converting the miscellany of electronic devices, many of them broken, into the components of a transmitter proceeded.

It was five years before the transmitter was ready for testing. It was early fall of the year thirty-five then, and the water that gushed from the pipe splashed in cold drops against Humbolt as the waterwheel was set in motion.

The generator began to hum and George observed the output of it and the transmitter as registered by the various meters he had made.

"Weak, but it will reach the Gern monitor station on Athena," he said. "It's ready to send-what do you want to say?"

"Make it something short," he said. "Make it 'Ragnarok calling.' "

George poised his finger over the transmitting key. "This will set forces in motion that can never be recalled. What we do here this morning is going to cause a lot of Gerns-or Ragnarok people-to die."

"It will be the Gerns who die," he said. "Send the signal."

"Like you, I believe the same thing," George said. "I have to believe it because that's the way I want it to be. I hope we're right. It's something we'll never know."

He began depressing the key.

A boy was given the job of operating the key and the signal went out daily until the freezing of winter stopped the waterwheel that powered the generator.

The sending of the signals was resumed when spring came and the prospecting parties continued their vain search for metals.

The suns continued moving south and each year the springs came later, the falls earlier. In the spring of forty-five he saw that he would have to make his final decision.

By then they dwindled until they numbered only sixty-eight; the Young Ones gray and rapidly growing old. There was no longer any use to continue the prospecting-if any metals were to be found they were at the north end of the plateau where the snow no longer melted during the summer. They were too few to do more than prepare for what the Old Ones had feared they might have to face-Big Winter. That would require the work of all of them.

Sheets of mica were brought down from the Craigs, the summits of which were deeply buried under snow even in midsummer. Stoves were made of fireclay and mica, which would give both heat and light and would be more efficient than open fireplaces.

The innermost caves were prepared for occupation, with multiple doors to hold out the cold and with laboriously excavated ventilation ducts and smoke outlets.

There were sixty of them in the fall of fifty, when all had been done that could be done to prepare for what might come.

"There aren't many of the Earth-born left now," Bob Craig said to him one night as they sat in the flickering light of a stove. "And there hasn't been time for there to be many of the Ragnarok-born. The Gerns wouldn't get many slaves if they should come now."

"They could use however many they found," he answered. "The younger ones, who are the best adapted to this gravity, would be exceptionally strong and quick on a one- gravity world. There are dangerous jobs where a strong, quick slave is a lot more efficient and expendable than complex, expensive machines."

"And they would want some specimens for scientific study," Jim Lake said. "They would want to cut into the young ones and see how they're built that they're adapted to this one and a half gravity world."

He smiled with the cold mirthlessness that always reminded Humbolt of his father- of the Lake who had been the Constellation's lieutenant commander. "According to the books the Gerns never did try to make it a secret that when a Gern doctor or biologist cuts into the muscles or organs of a non-Gern to see what makes them tick, he wants them to be still alive and ticking as he does so."

Seventeen-year-old Don Chiara spoke, to say slowly, thoughtfully: "Slavery and vivisection . . . If the Gerns should come now when there are so few of us, and if we should fight the best we could and lose, it would be better for whoever was the last of us left to put a knife in the hearts of the women and children than to let the Gerns have them."

No one made any answer. There was no answer to make, no alternative to suggest.

"In the future there will be more of us and it will be different," he said at last. "On Earth the Gerns were always stronger and faster than humans but when the Gerns come to Ragnarok they're going to find a race that isn't really human any more. They're going to find a race before which they'll be like woods goats before prowlers."

"If only they don't come too soon," Craig said.

"That was the chance that had to be taken," he replied.

He wondered again as he spoke, as he had wondered so often in the past years, if he had given them all their death sentence when he ordered the transmitter built. Yet, the future generations could not be permitted to forget . . . and steel could not be tempered without first thrusting it into the fire. * * *

He was the last of the Young Ones when he awoke one night in the fall of fifty-six and found himself burning with the h.e.l.l Fever. He did not summon any of the others.

They could do nothing for him and he had already done all he could for them.

He had done all he could for them . . . and now he would leave forty-nine men, women and children to face the unknown forces of Big Winter while over them hung the sword he had forged: the increasing danger of detection by the Gerns.

The question came again, sharp with the knowledge that it was far too late for him to change any of it. Did I arrange the execution of my people?

Then, through the red haze of the fever, Julia spoke to him out of the past; sitting again beside him in the summer twilight and saying: Remember me, Billy, and this evening, and what I said to you . . . teach them to fight and be afraid of nothing . . . never let them forget how they came to be on Ragnarok . . .

She seemed very near and real and the doubt faded and was gone. Teach them to fight . . . never let them forget . . . The men of Ragnarok were only fur-clad hunters who crouched in caves but they would grow in numbers as time went by. Each generation would be stronger than the generation before it and he had set forces in motion that would bring the last generation the trial of combat and the opportunity for freedom. How well they fought on that day would determine their destiny but he was certain, once again, what that destiny would be.

It would be to walk as conquerors before beaten and humbled Gerns.

Part 3

It was winter of the year eighty-five and the temperature was one hundred and six degrees below zero. Walter Humbolt stood in front of the ice tunnel that led back through the glacier to the caves and looked up into the sky.

It was noon but there was no sun in the starlit sky. Many weeks before the sun had slipped below the southern horizon. For a little while a dim halo had marked its pa.s.sage each day; then that, too, had faded away. But now it was time for the halo to appear again, to herald the sun's returning.

Frost filled the sky, making the stars flicker as it swirled endlessly downward. He blinked against it, his eyelashes trying to freeze to his lower eyelids at the movement, and turned to look at the north.

There the northern lights were a gigantic curtain that filled a third of the sky, rippling and waving in folds that pulsated in red and green, rose and lavender and violet. Their reflection gleamed on the glacier that sloped down from the caves and glowed softly on the other glacier; the one that covered the transmitter station. The transmitter had long ago been taken into the caves but the generator and waterwheel were still there, frozen in a tomb of ice.