Jupiter and the Jovian worlds leaped suddenly backward, turned swiftly green, then blue, and faded in an instant into violet. The Sun spun crazily through space, retreating, dimming to a tiny ruby-tinted star.

The giant generators in the Invincible hummed louder now, continually louder, a steel-throated roar that trembled through every plate, through every girder, through every bit of metal in the ship.

The ship itself was plunging spaceward, streaking like a runaway star for the depths of space beyond the Solar System. And behind it, caught tight, gripped and held, Craven’s ship trailed at the end of a tractor field that bound it to the space-rocketing Invincible.

The acceleration compensator, functioning perfectly, had taken up the slack as the ship had plunged from a standing start into a speed that neared the pace of light. But it had never been built to stand such sudden, intense acceleration, and for an instant Russ and Greg seemed to be crushed by a mighty weight that struck at them. The sensation swiftly lifted as the compensator took up the load.

Greg shook his head, flinging the trickling perspiration from his eyes.

“I hope their compensator worked as well as ours,” he said.

“If it didn’t,” declared Russ, “we’re towing a shipload of dead men.”

Russ glanced at the speed dial. They were almost touching the speed of light. “He hasn’t cut down our speed yet.”

“We threw him off his balance. His drive depends largely on the mass of some planet as a body to take up the reaction of his ship. Jupiter is the ideal body for that ... but he’s leaving Jupiter behind. He has to do something soon or it’ll be too late.”

“He’s getting less energy, too,” said Russ. “We’re retreating from his main sources of energy, the Sun and Jupiter. Almost the speed of light and that would cut down his energy intake terrifically. He has to use what he’s got in his accumulators, and after that last blast at us, they must be nearly drained.”

As Russ watched, the speed needle fell off slightly. Russ held his breath. It edged back slowly, creeping. The speed was being cut down.

“Craven is using whatever power he has,” he said. “They’re alive back there, all right. He’s trying to catch hold of Jupiter and make its gravity work for him.”

The Invincible felt the strain of the other ship now. Felt it as Craven poured power into his drive, fighting to get free of the invisible hawser that had trapped him, fighting against being dragged into outer space at the tail-end of a mighty craft heading spaceward with frightening speed.

Girders groaned in the Invincible, the engines moaned and throbbed. The speed needle fell back, creeping down the dial, slowly, unwillingly, resisting any drop in speed. But Craven was cutting it down. And as he cut it, he was able to absorb more energy with his collector lens. But he was fighting two things ... momentum and the steadily decreasing gravitational pull of Jupiter and the Sun. The Sun’s pull was dwindling slowly, Jupiter’s rapidly.

The needle still crept downward.

“What’s his point of equality to us?” demanded Greg. “Will we make it?”

Russ shook his head. “Won’t know for hours. He’ll be able to slow us up ... maybe he’ll even stop us or be able to jerk free, although I doubt that. But every minute takes him farther away from his main source of power, the Solar System’s radiation. He could collect power anywhere in space, you know, but the best place to collect it is near large radiant bodies.”

Russ continued to crouch over the dial, begrudging every backward flicker of the needle.

This was the last play, the final hand. If they could drag Craven and his ship away from the Solar System, maroon him deep in space, far removed from any source of radiation, they would win, for they could go back and finish the work of smashing Interplanetary.

But if Craven won if he could halt their mad dash for space, if he could shake free they’d never have another chance. He would be studying that field they had wrapped around him, be ready for it next time, might even develop one like it and use it on the Invincible. If Craven could win his way back to the Sun, he would be stronger than they were, could top them in power, shatter all their plans, and once again the worlds would bow to Interplanetary and Spencer Chambers.

Russ watched the meter. The speed was little more than ten miles a second now and dropping rapidly. He sat motionless, hunched, sucking at his dead pipe, listening to the thrumming of the generators.

“If we only had a margin,” he groaned. “If we just had a few more horsepower. Just a few. But we’re wide open. Every engine is developing everything it can!”

Greg tapped him on the shoulder, gently. Russ turned his head and looked into the face of his friend, a face as bleak as ever, but with a hint of smile in the corners of the eyes.

“Why not let Jupiter help us?” he asked. “He could be a lot of help.”

Russ stared for a moment, uncomprehending. Then with a sob of gladness he reached out a hand, shoved over a lever. Mirrors of anti-entropy shifted, assumed different angles, and the Invincible sheered off. They were no longer retreating directly from the Sun, but at an angle quartering off across the Solar System.

Greg grinned. “We’re falling behind Jupiter now. Letting Jupiter run away from us as he circles his orbit, following the Sun. Adds miles per second to our velocity of retreat, even if it doesn’t show on the dial.”

The cosmic tug of war went on, grimly two ships straining, fighting each other, one seeking to escape, the other straining to snake the second ship into the maw of open, hostile space.

The speed was down to five miles a second, then a fraction lower. The needle was flickering now, impossible to decide whether it was dropping or not. And in the engine rooms, ten great generators howled in their attempt to make that needle move up the dial again.

Russ lit his pipe, his eyes not leaving the dial. The needle was creeping lower again. Down to three miles a second now.

He puffed clouds of smoke and considered. Saturn fortunately was ninety degrees around in his orbit. On the present course, only Neptune remained between them and free space. Pluto was far away, but even if it had been, it really wouldn’t count, for it was small and had little attraction.

In a short while Ganymede and Callisto would be moving around on the far side of Jupiter and that might help. Everything counted so much now.

The dial was down to two miles a second and there it hung. Hung and stayed. Russ watched it with narrowed eyes. By this time Craven certainly would have given up much hope of help from Jupiter. If the big planet couldn’t have helped him before, it certainly couldn’t now. In another hour or two Earth would transit the Sun and that would cut down the radiant energy to some degree. But in the meantime Craven was loading his photo-cells and accumulators, was laying up a power reserve. As a last desperate resort he would use that power, in a final attempt to break away from the Invincible.

Russ waited for that attempt. There was nothing that could be done about it. The engines were developing every watt of power that could be urged out of them. If Craven had the power to break away, he would break away ... that was all there would be to it.

An hour passed and the needle crept up a fraction of a point. Russ was still watching the dial, his mind foggy with concentration.

Suddenly the Invincible shuddered and seemed to totter in space, as if something, some mighty force, had struck the ship a terrific blow. The needle swung swiftly backward, reached one mile a second, dipped to half a mile.

Russ sat bolt upright, holding his breath, his teeth clenched with death grip upon the pipe-stem.

Craven had blasted with everything he had! He had used every last trickle of power in the accumulators ... all the power he had been storing up.

Russ leaped from the chair and raced to the periscopic mirror. Stooping, he stared into it. Far back in space, like a silver bauble, swung Craven’s ship. It swung back and forth in space, like a mighty, cosmic pendulum. Breathlessly he watched. The ship was still in the grip of the space field!

“Greg,” he shouted, “we’ve got him!”

He raced back to the control panel, snapped a glance at the speed dial. The needle was rising rapidly now, a full mile a second. Within another fifteen minutes, it had climbed to a mile and a half. The Invincible was starting to go places!

The engines still howled, straining, shrieking, roaring their defiance.

In an hour the needle indicated the speed of four miles a second. Two hours later it was ten and rising visibly as Jupiter fell far behind and the Sun became little more than a glowing cinder.

Russ swung the controls to provide side acceleration and the two ships swung far to the rear of Neptune. They would pass that massive planet at the safe distance of a full hundred million miles.

“He won’t even make a pass at it,” said Greg. “He knows he’s licked.”

“Probably trying to store some more power,” suggested Russ.

“Sweet chance he has to do that,” declared Greg. “Look at that needle walk, will you? We’ll hit the speed of light in a few more hours and after that he may just as well shut off his lens. There just won’t be any radiation for him to catch.”

Craven didn’t make a try at Neptune. The planet was far away when they intersected its orbit ... furthermore, a wall of darkness had closed in about the ships. They were going three times as fast as light and the speed was still accelerating!

Hour after hour, day after day, the Invincible and its trailing captive sped doggedly outward into space. Out into the absolute wastes of interstellar space, where the stars were flecks of light, like tiny eyes watching from very far away.

Russ lounged in the control chair and stared out the vision plate. There was nothing to see, nothing to do. There hadn’t been anything to see or do for days. The controls were locked at maximum and the engines still hammered their roaring song of speed and power. Before them stretched an empty gulf that probably never before had been traversed by any intelligence, certainly not by man.

Out into the mystery of interstellar space. Only it didn’t seem mysterious. It was very commonplace and ordinary, almost monotonous. Russ gripped his pipe and chuckled.

There had been a day when men had maintained one couldn’t go faster than light. Also, men had claimed that it would be impossible to force nature to give up the secret of material energy. But here they were, speeding along faster than light, their engines roaring with the power of material energy.

They were plowing a new space road, staking out a new path across the deserts of space, pioneering far beyond the ‘last frontier.’

Greg’s steps sounded across the room. “We’ve gone a long way, Russ. Maybe we better begin to slow down a bit.”

“Yes,” agreed Russ. He leaned forward and grasped the controls. “We’ll slow down now,” he said.

Sudden silence smote the ship. Their ears, accustomed for days to the throaty roarings of the engines, rang with the torture of no sound.

Long minutes and then new sounds began to be heard ... the soft humming of the single engine that provided power for the interior apparatus and the maintenance of the outer screens.

“Soon as we slow down below the speed of light,” said Greg, “we’ll throw the televisor on Craven’s ship and learn what we can about his apparatus. No use trying it now, for we couldn’t use it, because we’re in the same space condition it uses in normal operation.”

“In fact,” laughed Russ, “we can’t do much of anything except move. Energies simply can’t pass through this space we’re in. We’re marooned.”

Greg sat down in a chair, gazed solemnly at Russ.

“Just what was our top speed?” he demanded.

Russ grinned. “Ten thousand times the speed of light,” he said.

Greg whistled soundlessly. “A long way from home.”

Far away, the stars were tiny pinpoints, like little crystals shining by the reflection of a light. Pinpoints of light and shimmering masses of lacy silver ... star dust that seemed ghostly and strange, but was in reality the massing of many million mighty stars. And great empty black spaces where there was not a single light, where the dark went on and on and did not stop.

Greg exhaled his breath softly. “Well, we’re here.”

“Wherever that might be,” amended Russ.

There were no familiar constellations, not a single familiar star. Every sign post of the space they had known was wiped out.

“There really aren’t any brilliant stars,” said Russ. “None at all. We must be in a sort of hole in space, a place that’s relatively empty of any stars.”

Greg nodded soberly. “Good thing we have those mechanical shadows. Without them we’d never find our way back home. But we have several that will lead us back.”

Outside the vision panel, they could see Craven’s ship. Freed now of the space field, it was floating slowly, still under the grip of the momentum they had built up in their dash across space. It was so close that they could see the lettering across its bow.

“So they call it the Interplanetarian,” said Russ.

Greg nodded. “Guess it’s about time we talk to them. I’m afraid they’re getting pretty nervous.”

“Do you have any idea where we are?” demanded Ludwig Stutsman.

Craven shook his head. “No more idea than you have. Manning snaked us across billions of miles, clear out of the Solar System into interstellar space. Take a look at those stars and you get some idea.”

Spencer Chambers stroked his gray mustache, asked calmly: “What do you figure our chances are of getting back?”

“That’s something we’ll know more about later,” said Craven. “Doesn’t look too bright right now. I’m not worrying about that. What I’m wondering about is what Manning and Page are going to do now that they have us out here.”

“I thought you’d be,” said a voice that came out of clear air.

They stared at the place from which the voice had seemed to come. There was a slight refraction in the air; then, swiftly, a man took shape. It was Manning. He stood before them, smiling.

“Hello, Manning,” said Craven. “I figured you’d pay us a call when you got around to it.”

“Look here,” snarled Stutsman, but he stopped when Chambers’ hand fell upon his shoulder, gripped it hard.

“Got plenty of air?” asked Greg.

“Air? Sure. Atmosphere machines working perfectly,” Craven replied.

“Fine,” said Greg. “How about food and water? Plenty of both?”

“Plenty,” said Craven.

“Look here, Manning,” broke in Chambers, “where’s all this questioning leading? What have you got up your sleeve?”

“Just wanted to be sure,” Greg told him. “Would hate to have you fellows starve on me, or go thirsty. Wouldn’t want to come back and find you all dead.”

“Come back?” asked Chambers wonderingly. “I’m afraid I don’t understand. Is this a joke of some sort?”

“No joke,” said Greg grimly. “I thought you might have guessed. I’m going to leave you here.”

“Leave us here?” roared Stutsman.

“Keep your shirt on,” snapped Greg. “Just for a while, until we can go back to the Solar System and finish a little job we’re doing. Then we’ll come back and get you.”

Craven grimaced. “I thought it would be something like that.” He squinted at Manning through the thick lenses. “You never miss a bet, do you?”

Greg laughed. “I try not to.”

A little silence fell upon the three men and Manning’s image.

Greg broke it. “How about your energy collector?” he asked Craven. “Will it maintain the ship out here? You get cosmic rays. Not too much else, I’m afraid.”

Craven grinned wryly. “You’re right, but we can get along. The accumulators are practically drained, though, and we won’t be able to store anything. Would you mind shooting us over just a little power? Enough to charge the accumulators a little for emergency use.”

He looked over his shoulder, almost apprehensively.

“There might be an emergency out here, you know. Nobody knows anything about this place.”

“I’ll give you a little power,” Greg agreed.

“Thank you very much,” said Craven, half in mockery. “No doubt you think yourself quite smart, Manning, getting us out here. You know you have us stranded, that we can’t collect more than enough power to live on.”

“That’s why I did it,” Greg said, and vanished.