The four earthmen watched the fleet of alien ships roar through the air toward them.

"Now how shall we signal them?" asked Morey, also trying to be nonchalant, and failing as badly as Arcot had.

"Don't try the light beam method," cautioned Arcot. The last time they had tried to use a light beam signal was when they first contacted the Nigrans. The Nigrans thought it was some kind of destruction ray. That had started the terrible destructive war of the Black Star.

"Let's just hang here peaceably and see what they do," Arcot suggested.

Motionless, the Ancient Mariner hung before the advancing attack of the great battle fleet. The shining hull was a thing of beauty in the golden sunlight as it waited for the advancing ships.

The alien ships slowed as they approached and spread out in a great fan-shaped crescent.

Suddenly, the Ancient Mariner gave a tremendous leap and hurtled toward them at a terrific speed, under an acceleration so great that Arcot was nearly hurled into unconsciousness. He would have been except for the terrific mass of the ship. To produce that acceleration in so great a mass, a tremendous force was needed, a force that even made the enemy fleet reel under its blow!

But, sudden as it was, Arcot had managed to push the power into reverse, using the force of the molecular drive to counteract the attraction the aliens had brought to bear.

The whole mighty fabric of the ship creaked as the titanic load came upon it. They were using a force of a million tons!

The mighty lux beams withstood the stress, however, and the ship came to a halt, then was swiftly backing away from the alien battle fleet.

"We can give them all they want!" said Arcot grimly. He noticed that Wade and Fuller had been knocked out by the sudden blow, but Morey, though slightly groggy, was still in possession of his senses.

"Let's not," Morey remonstrated. "We may be able to make friends with them, but not if we kill them off."

"Right!" replied Arcot, "but we're going to give them a little demonstration of power!"

The Ancient Mariner leaped suddenly upward with a speed that defied the eyes of the men at the rays of the enemy ships. Then, as they turned to follow the sudden motion of the ship—it was not there!

The Ancient Mariner had vanished!

Morey was startled for an instant as the ship and his companions disappeared around him, then he realized what had happened. Arcot had used the invisibility apparatus!

Arcot turned and raced swiftly far off to one side, behind the strange ships, and hovered over the great cliff that made the edge of the cleft that was the river bed. Then he snapped the ship into full visibility.

Wade and Fuller had recovered by now, and Arcot started barking out orders. "Wade—Fuller—take the molecular ray, Wade, and tear down that cliff—throw it down into the valley. Fuller, turn the heat beams on with all the power you can get and burn that refuse he tears down into a heap of molten lava!

"I'm going to show them what we can do! And, Wade—after Fuller gets it melted down, throw the molten lava high in the air!"

From the ship, a long pencil of rays, faintly violet from the air they ionized, reached out and touched the cliff. In an instant, it had torn down a vast mass of the solid rock, which came raining down into the valley with a roaring thunder and threw the dirt of the valley into the air like splashed mud.

Then the violet ray died, and two rays of blinding brilliance reached out. The rock was suddenly smoking, steaming. Then it became red, dull at first, then brighter and brighter. Suddenly it collapsed into a great pool of white-hot lava, flowing like water under the influence of the beams from the ship.

Again the pale violet of the molecular beams touched the rock—which was now bubbling lava. In an instant, the great mass of flaming incandescent rock was flying like a glowing meteor, up into the air. It shot up with terrific speed, broke up in mid-air, and fell back as a rain of red-hot stone.

The bright rays died out, but the pale fingers of the molecular beams traced across the level ground. As they touched it, the solid soil spouted into the air like some vast fountain, to fall back as frost-covered powder.

The rays that had swung a sun into destruction were at work! What chance had man, or the works of man against such? What mattered a tiny planet when those rays could hurl one mighty sun into another, to blaze up in an awful conflagration that would light up space for a million light years around with a mighty glare of light!

As if by a giant plow, the valley was torn and rent in great streaks by the pale violet rays of the molecular force. Wade tore loose a giant boulder and sent it rocketing into the heavens. It came down with a terrific crash minutes later, to bury itself deep in the soil as it splintered into fragments.

Suddenly the Ancient Mariner was jerked violently again. Evidently undaunted by their display of power, the aliens' rays had gripped the Earthmen's ship again and were drawing it with terrific acceleration. But this time the ship was racing toward the city, caught by the beam of one of the low-built, sturdy buildings that housed the protective ray projectors.

Again Arcot threw on the mighty power units that drove the ship, bracing them against the pull of the beam.

"Wade! Use the molecular ray! Stop that beam!" Arcot ordered.

The ship was stationary, quivering under the titanic forces that struggled for it. The enemy fleet raced toward them, trying to come to the aid of the men in the tower.

The pale glow of the molecular beam reached out its ghostly finger and touched the heavy-walled ray projector building. There was a sudden flash of discharging energy, and the tower was hurled high in the air, leaving only a gaping hole in the ground.

Instantly, with the collapse of the beam that held it, the Ancient Mariner shot backward, away from the scene of the battle. Arcot snapped off the drive and turned on the invisibility apparatus. They hung motionless, silent and invisible in the air, awaiting developments.

In close formation, one group of ships blocked the opening in the wall of rays that the removal of one projector building had caused. Three other ships went to investigate the wreck of the building that had fallen a mile away.

The rest of the fleet circled the city, darting around, searching frantically for the invisible enemy, fully aware of the danger of collision. The unnerving tension of expecting it every second made them erratic and nervous to the nth degree.

"They're sticking pretty close to home," said Arcot. "They don't seem to be too anxious to play with us."

"They don't, do they?" Morey said, looking angry. "They might at least have been willing to see what we wanted. I want to investigate some other cities. Come on!" He had thoroughly enjoyed the rest at the little mountain lake, and he was disappointed that they had been driven away. Had they wanted to, he knew, they could easily have torn the entire city out by the roots!

"I think we ought to smash them thoroughly," said Wade. "They're certainly inhospitable people!"

"And I, for one, would like to know what that attraction ray was," said Fuller curiously.

"The ray is easily understood after you take a look at the wreck it made of some of these instruments," Arcot told him. "It was projected magnetism. I can see how it might be done if you worked on it for a while. The ray simply attracted everything in its path that was magnetic, which included our lux metal hull.

"Luckily, most of our apparatus is shielded against magnetism. The few things that aren't can be repaired easily. But I'll bet Wade finds his gear in the galley thrown around quite a bit."

"Where do we go from here, then?" Wade asked.

"Well, this world is bigger than Earth," said Morey. "Even if they're afraid to go out of their cities to run farms, they must have other cities. The thing that puzzles me, though, is how they do it—I don't see how they can possibly raise enough food for a city in the area they have available!"

"'People couldn't possibly live in hydrogen instead of oxygen'," Arcot quoted, grinning. "That's what they told me when I made my little announcement at the meeting on the Black Star situation. The only trouble was—they did. That suggestion of yours meets the same fate, Morey!"

"All right, you win," agreed Morey. "Now let's see if we can find the other nations on this world more friendly."

Arcot looked at the sun. "We're now well north of the equator. We'll go up where the air is thin, put on some speed, and go into the south temperate zone. We'll see if we can't find some people there who are more peaceably inclined."

Arcot cut off the invisibility tubes. Instantly, all the enemy ships in the neighborhood turned and darted toward them at top speed. But the shining Ancient Mariner darted into the deep blue vault of the sky, and a moment later was lost to their view.

"They had a lot of courage," said Arcot, looking down at the city as it sank out of sight. "It doesn't take one-quarter as much courage to fight a known enemy, no matter how deadly, as it does to fight an unknown enemy force—something that can tear down mountains and throw their forts into the air like toys."

"Oh, they had courage, all right," Morey conceded, "but I wish they hadn't been quite so anxious to display it!"

They were high above the ground now, accelerating with a force of one gravity. Arcot cut the acceleration down until there was just enough to overcome the air resistance, which, at the height they were flying, was very low. The sky was black above them, and the stars were showing around the blazing sun. They were unfamiliar stars in unfamiliar constellations—the stars of another universe.

In a very short time, the ship was dropping rapidly downward again, the horizontal power off. The air resistance slowed them rapidly. They drifted high over the south temperate zone. Below them stretched the seemingly endless expanse of a great blue-green ocean.

"They don't lack for water, do they?" Wade commented.

"We could pretty well figure on large oceans," Arcot said. "The land is green, and there are plenty of clouds."

Far ahead, a low mass of solid land appeared above the blue of the horizon. It soon became obvious that it was not a continent they were approaching, but a large island, stretching hundreds of miles north and south.

Arcot dropped the ship lower; the mountainous terrain had become so broken that it would be impossible to detect a city from thirty miles up.

The green defiles of the great mountains not only provided good camouflage, but kept any great number of ships from attacking the sides, where the ray stations were. The cities were certainly located with an eye for war! Arcot wondered what sort of conflict had lasted so long that cities were designed for perpetual war. Had they never had peace?

"Look!" Fuller called. "There's another city!" Below them, situated in a little natural bowl in the mountains, was another of the cone cities.

Wade and Fuller manned the ray projectors again; Arcot dropped the ship toward the city, one hand on the reverse switch in case the inhabitants tried to use the magnetic beam again.At last, they had come quite low. There were no ships in the air, and no people in sight.

Suddenly, the outside microphone picked up a low, humming sound. A long, cigar-shaped object was heading toward the ship at high speed. It had been painted a dark, mottled green, and was nearly invisible against background of foliage beneath the ship.

"Wade! Catch that on the ray!" Arcot commanded sharply, moving the ship to one side at the same time. Instantly, the guided missile turned and kept coming toward them.

Wade triggered the molecular beam, and the missile was suddenly dashing toward the ground with terrific speed. There was a terrific flash of flame and a shock wave of concussion. A great hole gaped in the ground.

"They sure know their chemistry," remarked Wade, looking down at the great hole the explosion had torn in the ground. "That wasn't atomic, but on the other hand, it wasn't dynamite or TNT, either! I'd like to know what they use!"

"Personally," said Arcot angrily, "I think that was more or less a gentle hint to move on!" He didn't like the way they were being received; he had wanted to meet these people. Of course, the other planet might be inhabited, but if it wasn't—

"I wonder—" said Morey thoughtfully. "Arcot, those people were obviously warned against our attack—probably by that other city. Now, we've come nearly halfway around this world; certainly we couldn't have gone much farther away and still be on the planet. And we find this city in league with the other! Since this league goes halfway around the world, and they expected us to do the same, isn't it fair to assume, just on the basis of geographical location, that all this world is in one league?"

"Hmmm—an interplanetary war," mused Arcot. "That would certainly prove that one of the other planets is inhabited. The question is—which one?"

"The most probable one is the next inner planet, Aphrodite," replied Morey.Arcot fired the ship into the sky. "If your conclusions are correct—and I think they are—I see no reason to stay on this planet. Let's go see if their neighbors are less aggressive!"

With that, he shot the ship straight up, rotating the axis until it was pointing straight away from the planet. He increased the acceleration until, as they left the outer fringes of the atmosphere, the ship was hitting a full four gravities.

"I'm going to shorten things up and use the space control," Arcot said. "The gravitational field of the sun will drain a lot of our energy out, but so what? Lead is cheap, and before we're through, we'll have plenty or I'll know the reason why!"

Dr. Richard Arcot was angry—boiling all the way through!