Transcriber's Note:

 This etext was produced from Astounding Stories March 1933. Extensive research did not uncover any evidence that the U. S. Copyright on this publication was renewed. 

 [Illustration: He picked Sylva up in his arms and ran madly. ]

 Invasion

 By Murray Leinster

 * * * * *

[Sidenote: The whole fighting fleet of the United Nations is caught inKreynborg's marvelous, unique trap. ]

It was August 19, 2037. The United Nations was just fifty years old. Televisors were still monochromatic. The Nidics had just won the WorldSeries in Prague. Com-Pub observatories were publishing elaboratefigures on moving specks in space which they considered to be Martianspaceships on their way to Earth, but which United Nations astronomerscould not discover at all. Women were using gilt lipsticks that year. Heat-induction motors were still considered efficient prime movers. 

Thorn Hard was a high-level flier for the Pacific Watch. Bathyletiswas the most prominent of nationally advertised diseases, and was tobe cured by RO-17, "The Foundation of Personal Charm. " Somebody namedNirdlinger was President of the United Nations, and somebody elsenamed Krassin was Commissar of Commissars for the Com-Pubs. Newspaperswere printing flat pictures in three colors only, and deploring thehigh cost of stereoscopic plates. And . .. Thorn Hard was a high-levelflier for the Pacific Watch. 

That is the essential point, of course--Thorn Hard's work with theWatch. His job was, officially, hanging somewhere above thetwenty-thousand-foot level with his detector-screens out, listeningfor unauthorized traffic. And, the normal state of affairs between theCom-Pubs and the United Nations being one of highly armed truce, "unauthorized traffic" meant nothing more or less than spies. 

But on August 19th, 2037, Thorn Hard was off duty. Decidedly so. Hewas sitting on top of Mount Wendel, in the Rockies; he had aravishingly pretty girl sitting on the same rock with him, and he waslooking at the sunset. The plane behind him was an official Watchplane, which civilians are never supposed to catch a glimpse of. Ithad brought Thorn Hard and Sylva West to this spot. It waited now, half-hidden by a spur of age-eroded rock, to take them back tocivilization again. Its G. C. (General Communication) phone mutteredoccasionally like the voice of conscience. 

[Illustration:]

The colors of the mountain changed and blended. The sky to westwardwas a glory of a myriad colors. Man and girl, high above the world, sat with the rosy glow of dying sunlight in their faces and watchedthe colors fade and shift into other colors and patterns even moreexquisite. Their hands touched. They looked at each other. Theysmiled queerly, as people smile who are in love or otherwise not quitesane. They moved inevitably closer. .. . 

And then the G. C. Phone barked raucously:

"All Watch planes attention! Urgent! Extreme high-level trafficreported seven-ten line bound due east, speed over one thousand. AllWatch planes put out all detectors and use extra vigilance. Note: thespeed, course, and time of report of this traffic checks with Com-Pubobservations of moving objects approaching Earth from Mars. Thispossibility should be considered before opening fire. "

Thorn Hard stiffened all over. He got up and swung down to the stubbylittle ship with its gossamer-like wings of cellate. He touched thereport button. 

"Plane 257-A reporting seven-ten line. Thorn Hard flying. On MountWendel, on leave. Orders?"

He was throwing on the screens even as he reported. And the verticaldetector began to whistle shrilly. His eyes darted to the dial, and hespoke again. 

"Added report. Detector shows traffic approaching, bound due east, seven hundred miles an hour, high altitude. .. . Correction; six-fiftymiles. Correction; six hundred. " He paused. "Traffic is deceleratingrapidly. I think, sir, this is the reported ship. "

 * * * * *

And then there was a barely audible whining noise high in the air tothe west. It grew in volume and changed in pitch. From a whine itbecame a scream. From a scream it rose to a shriek. Somethingmonstrous and red glittered in the dying sunlight. It was huge. It wasof no design ever known on earth. Wings supported it, but they wereobscured by the blasts of forward rockets checking its speed. 

It was dropping rapidly. Then lifting-rockets spouted flame to keep itfrom too rapid a descent. It cleared a mountain-peak by a bare twohundred feet, some two miles to the south. It was a hundred-odd feetin length. It was ungainly in shape, monstrous in conformation. Colossal rocket-tubes behind it now barely trickled vaporousdischarges. It cleared the mountain-top, went heavily on in a steepglide downward, and vanished behind a mountain-flank. Presently thethin mountain air brought the echoed sound of its landing, ofrapid-fire explosions of rocket-tubes, and then silence. 

Thorn Hard was snapping swift, staccato sentences into thereport-transmitter. Describing the clumsy glittering monster, itsmotion; its wings; its method of propulsion. It seemed somehowfamiliar despite its strangeness. He said so. 

Then a vivid blue flame licked all about the rim of the world and wasgone. Simultaneously the G. C. Speaker crashed explosively and wentdead. Thorn went on grimly, switching in the spare. 

"A very violent electrical discharge went out from it then. A bluelight seemed to flash all around the horizon at no great distance andmy speaker blew out. I have turned on the spare. I do not know whethermy sender is functioning--"

The spare speaker cut in abruptly at that moment:

"It is. Stay where you are and observe. A squadron is coming. "

 * * * * *

Then the voice broke off, because a new sound was coming from thespeaker. It was a voice that was unhuman and queerly horrible andsomehow machine-like. Hoots and howls and whistles came from thespeaker. Wailing sounds. Ghostly noises, devoid of consonants butbroadcast on a wave-length close to the G. C. Band and thereforeproduced by intelligence, though unintelligible. The unhuman hoots andwails and whistles came through for nearly a minute, and stopped. 

"Stay on duty!" snapped the G. C. Speaker. "That's no language known onearth. Those are Martians!"

Thorn looked up to see Sylva standing by the Watch-plane door. Herface was pale in the growing darkness outside. 

"Beginning duty sir, " said Thorn steadily, "I report that I have withme Miss Sylva West, my fiancée, in violation of regulations. I askthat her family be notified. "

He snapped off the lights and went with her. The red rocket-ship hadlanded in the very next valley. There was a glare there, which waveredand flickered and died away. 

"Martians!" said Thorn in fine irony. "We'll see when the Watch planescome! My guess is Com-Pubs, using a searchlight! Nervy!"

The glare vanished. There was only silence, a curiously complete anddeadly silence. And Thorn said, suddenly:

"There's no wind!"

There was not. Not a breath of air. The mountains were uncannilyquiet. The air was impossibly still, for a mountain-top. Ten minuteswent by. Twenty. The detector-whistles shrilled. 

"There's the Watch, " said Thorn in satisfaction. "Now we'll see!"

And then, abruptly, there was a lurid flash in the sky to northward. Two thousand feet up and a mile away, the unearthly green blaze of ahexynitrate explosion lit the whole earth with unbearable brilliance. 

"Stop your ears!" snapped Thorn. 

 * * * * *

The racking concussion-wave of hexynitrate will break human eardrumsat an incredible distance. But no sound came, though the seconds wentby. .. . Then, two miles away, there was a second gigantic flash. .. . Then a third. .. . But there was no sound at all. The quiet of the hillsremained unbroken, though Thorn knew that such cataclysmic detonationsshould be audible at twenty miles or more. Then lights flashed onabove. Two--three--six of them. They wavered all about, darting hereand there. .. . Then one of the flying searchlights vanished utterly ina fourth terrific flash of green. 

"The watch planes are going up!" said Thorn dazedly. "Blowing up! Andwe can't hear the explosions!"

Behind him the G. C. Speaker barked his call. He raced to get itsmessage. 

"The Watch planes we sent to join you, " said a curt voice herecognized as that of the Commanding General of the United Nations, "have located an invisible barrier by their sonic altimeters. Four ofthem seem to have rammed it and exploded without destroying it. Whathave you to report?"

"I've seen the flashes, sir, " said Thorn unsteadily, "but they made nonoise. And there's no wind, sir. Not a breath since the blue flash Ireported. "

A pause. 

"Your statement bears out their report, " said the G. C. Speakerharshly. "The barrier seems to be hemispherical. No such barrier isknown on Earth. These must be Martians, as the Com-Pubs said. You willwait until morning and try to make peaceful contact with them. Thisbarrier may be merely a precaution on their part. You will try toconvince them that we wish to be friendly. "

"I don't believe they're Martians, sir--"

Sylva came racing to the door of the plane. 

"Thorn! Something's coming! I hear it droning!"

Thorn himself heard a dull droning noise in the air, coming towardhim. 

"Occupants of the rocket-ship, sir, " he said grimly, "seem to beapproaching. Orders?"

"Evacuate the ship, " snapped the G. C. Phone. "Let them examine it. They will understand how we communicate and prepare to receive andexchange messages. If they seem friendly, make contact at once. "

 * * * * *

Thorn made swift certain movements and dived for the door. He seizedSylva and fled for the darkness below the plane. He was taking adesperate risk of falling down the mountain-slopes. The droning drewnear. It passed directly overhead. Then there was a flash and adeafening report. A beam of light appeared aloft. It searched for andfound Thorn's plane, now a wreck. Flash after flash and explosionafter explosion followed. .. . 

They stopped. Their echoes rolled and reverberated among the hills. There was a hollow, tremendous intensification of the echoes aloft asif a dome of some solid substance had reflected back the sound. Slowlythe rollings died away. Then a voice boomed through a speakeroverhead, and despite his suspicions Thorn felt a queer surprise. Itwas a human voice, a man's voice, full of a horrible amusement. 

"Thorn Hardt! Thorn Hardt! Where are you?" Thorn did not move orreply. "If I haff not killed you, you hear me, " the voice chuckled. "Come to see me, Thorn Hardt. Der dome of force iss big, yes, but youcan no more get out than your friends can get in. And now I haffdestroyed your phones so you can no longer chat with them. Come andsee me, Thorn Hardt, so I will not be bored. We will discuss derCom-Pubs. And bring der lady friend. You may play der chaperon!"

The voice laughed. It was not pleasant laughter. And the humming dronein the air rose and dwindled. It moved away from the mountain-top. Itlessened and lessened until it was inaudible. Then there was deadsilence again. 

"By his accent, he's a Baltic Russian, " said Thorn very grimly in thedarkness. "Which means Com-Pubs, not Martians, though we're the onlypeople who realize it; and they're starting a war! And we, Sylva, mustwarn our people. How are we going to do it?"

She pressed his hand confidently, but it did not look promising. ThornHard was on foot, without a transmitter, armed only with hisbelt-weapons and with a girl to look after, and moreover imprisoned ina colossal dome of force which hexynitrate had failed to crack. .. . 

 * * * * *

It was August 20, 2037. There was a triple murder in Paris which wasrumored to be the work of a Com-Pub spy, though the murderer'sunquestionably Gallic touches made the rumor dubious. Newspapervendor-units were screaming raucously, "Martians land in Colorado!"and the newspapers themselves printed colored-photos of hastilyimprovised models in their accounts of the landing of a blood-redrocket-ship in the widest part of the Rockies. The inter-continentaltennis matches reached their semi-finals in Havana, Cuba. Thorn Hardhad not reported to Watch headquarters in twelve hours. Quadrupletswere born in Des Moines, Iowa. Krassin, Commissar of Commissars of theCom-Pubs, made a diplomatic inquiry about the rumors that a Martianspace-ship had landed in North America. He asked that Com-Pubscientists be permitted to join in the questioning and examination ofthe Martian visitors. The most famous European screen actress landedfrom the morning Trans-Atlantic plane with her hair dyed a lightlavender, and beauty-shops throughout the country placed rush ordersfor dye to take care of the demand for lavender hair which would beginby mid-afternoon. The heavy-weight champion of the United Nations waswarned that his title would be forfeited if he further dodged a fightwith his most promising contender. And . .. Thorn Hard had not reportedto Watch headquarters in twelve hours. 

He was, as a matter of fact, cautiously parting some bushes to peerpast a mountain-flank at the red rocket-ship. Sylva West lay on theground behind him. Both of them weary to the point of exhaustion. Theyhad started their descent from Mount Wendel at the first gray streakof dawn in the east. They had toiled painfully across the brokencountry between, to this point of vantage. Now Thorn looked down uponthe rocket-ship. 

 * * * * *

It lay a little askew upon the ground, seeming to be partly buried inthe earth. A hundred feet and more in length, it was even moreobviously a monstrosity as he looked at it in the bright light of day. But now it was not alone. Beside it a white tower reared upward. Purewhite and glistening in the sunshine, a bulging, uneven shaft rose ahundred feet sheer. It looked as solid as marble. Its purpose wasunguessable. There was a huge, fan-shaped space where the vegetationabout the rocket-ship was colored a vivid red. In air-photos, therocket-ship would look remarkably like something from another planet. But nearby, Thorn could see a lazy trickle of fuel-fumes from aport-pipe on one side of the monster. .. . 

"That tower is nothing but cellate foam, which hardens. And Sylva!See?"

She came cautiously through the brushwood and looked down. Sheshivered a little. From here they could see beneath the bows of therocket-ship. And there was a name there, in the Cyrillic alphabetwhich was the official written language of the Com-Pubs. Here, onUnited Nations soil, it was insolent. It boasted that the red shipcame, not from an alien planet, but from a nation more alien still toall the United Nations stood for. The Com-Pubs--the Union of CommunistRepublics--were neither communistic nor republics, but they were muchmore dangerous to the United Nations than any mere Martians would havebeen. 

"We'll have some heavy ships here to investigate, soon, " said Thorngrimly. "Then I'll signal!"

 * * * * *

He flung back his head. High up and far away, beyond that invisiblebarrier against which Watch-planes had flung themselves in vain, therewere tiny motes in mid-air. These were Watch planes too, hoveringoutside the obstacle they could not see, but which even hexynitratebombs could not break through. And very far away indeed there was aswiftly-moving small dark cloud. As Thorn watched, that cloud drewclose. As his eyes glowed, it resolved itself into its componentspecks. Small, two-man patrol-scouts. Larger, ten-man cruisers of theair. Huge, massive dreadnaughts of the blue. A completecombat-squadron of the United Nations Fighting Forces was sweeping toposition about the dome of force above the rocket-ship. 

The scouts swept forward in a tiny, whirling cloud. They sheered awayfrom something invisible. One of them dropped a smoking object. Itemitted a vast cloud of paper, which the wind caught and swept away, and suddenly wrapped about a definite section of an arc. More and moreof the tiny smoke-bombs released their masses of cloudlike stuff. Inmid-air a dome began to take form, outlined by the trailing streaks ofgray. It began to be more definitely traced by interlinings. An aeriallattice spread about a portion of a six-mile hemisphere. The top wasfifteen thousand feet above the rocket-ship, twenty-five thousand feetfrom sea-level, as high as Mount Everest itself. 

Tiny motes hovered even there, where the smallest of visible speckswas a ten-man cruiser. And one of the biggest of the aircraft camegingerly up to the very inner edge of the lattice-work of fog and hungmotionless, holding itself aloft by powerful helicopter screws. Menwere working from a trailing stage--scientists examining the barriereven hexynitrate would not break down. 

 * * * * *

Thorn set to work. He had come toilsomely to the neighborhood of therocket-ship because he would have to do visual signaling, and therewas no time to lose. The dome of force was transparent. The air fleetwould be trying to communicate through it with the Martians theybelieved were in the rocket-ship. Sunlight reflected from a polishedcanteen would attract attention instantly from a spot near the redmonster, while elsewhere it might not be observed for a long time. But, trying every radio wave-band, and every system of visualsignaling, and watching and testing for a reply, Thorn's signal oughtto be picked up instantly. 

He handed his pocket speech-light receptor to Sylva. It is standardequipment for all flying personnel, so they may receive non-broadcastorders from flight leaders. He pointed to a ten-man cruiser fromwhich shone the queer electric-blue glow of a speech-light. 

"Listen in on that, " he commanded. "I'm going to call them. Tell mewhen they answer. "

He began to flash dots and dashes in that quaintly archaic telegraphalphabet Watch fliers are still required to learn. It was the Watchcode call, sent over and over again. 

"They're trying to make the Martians understand, " said Sylvaunsteadily with the speech-light receiver at her ear. 

 * * * * *

Flash--flash--flash. .. . Thorn kept on grimly. The canteen top wasslightly convex, so the sunlight-beam would spread. Accuracy was notneeded, therefore. He covered and uncovered it, and covered anduncovered it. .. . 

"They answered!" said Sylva eagerly. "They said 'Thorn Hard report atonce!'"

There was a hissing, roaring noise over the hillside, where the redrocket-ship lay. Thorn paid no attention. He began to spell out, ingrim satisfaction:

"R-o-c-k-e-t s-h-i-p i-s--"

"Look out!" gasped Sylva. "They say look out, Thorn!"

Then she screamed. As Thorn swung his head around, he saw a dense massof white vapor rushing over the hillside toward them. He picked Sylvaup in his arms and ran madly. .. . 

The white vapor tugged at his knees. It was a variation of avortex-stream. He fought his way savagely toward higher ground. Thewhite vapor reached his waist. .. . It reached his shoulders. .. . Heslung Sylva upon his shoulder and fought more madly still to get outof the wide white current. .. . It submerged him in its stinging, bitterflood. .. . As he felt himself collapsing his last conscious thought wasthe bitter realization that the bulbous white tower had upheldtelevision lenses at its top, which had watched his approach andinspection of the rocket-ship, and had enabled those in the redmonster to accurately direct their spurt of gas. 

His next sensation was that of pain in his lungs. Something thatsmarted intolerably was being forced into his nostrils, and he battledagainst the agony it produced. And then he heard someone chuckleamusedly and felt the curious furry sensation of electric anesthesiabeginning. .. . 

 * * * * *

When he came to himself again a machine was clicking erratically andthere was the soft whine of machinery going somewhere. He opened hiseyes and saw red all about him. He stirred, and he was free. Painfully, he sat up and blinked about him with streaming, gas-irritated eyes. He had been lying on a couch. He was in a roomperhaps fifteen feet by twenty, of which the floor was slightlyoff-level. And everything in the room was red. Floor and walls andceiling, the couch he had lain on and the furniture itself. There wasa monstrous bulk of a man sitting comfortably in a chair on the otherside of the room, pecking at a device resembling a writing-machine. 

Thorn sat still for an instant, gaining strength. Then he flunghimself desperately across the room, his fingers curved into talons. 

Five feet, ten, with the slant of the floor giving him addedimpetus. .. . Then his muscles tightened convulsively. A wave of pureagony went through his body. He dropped and lay writhing on the floor, while the high-frequency currents of an induction-screen had their waywith him. He was doubled into a knot by his muscles responding to theelectric stimulus instead of his will. Sheer anguish twisted him. Andthe room filled with a hearty bellow of laughter. The monstrouswhiskered man had turned about and was shaking with merriment. 

He picked up a pocket-gun from beside him and turned off a switch athis elbow. Thorn's muscles were freed. 

"Go back, my friendt, " boomed the same voice that had come from aspeaker the night before. "Go to der couch. You amuse me and you haffalready been useful, but I shall haff no hesitation in killing you. You are Thorn Hardt. My name is Kreynborg. How do you do?"

"Where's my friend?" demanded Thorn savagely. "Where is she?"

"Der lady friendt? There!" The whiskered man pointed negligently withthe pocket-gun. "I gafe her a bunk to slumber in. "

 * * * * *

There was a niche in the wall, which Thorn had not seen. Sylva wasthere, sleeping the same heavy, dreamless sleep from which Thornhimself had just awakened. He went to her swiftly. She was breathingnaturally, though tears from the irritating gas still streaked herface and her skin seemed to be pinkened a little from the same cause. 

Thorn swung around. His weapons were gone, of course. The huge mansnapped on the induction-screen switch again and put down his weapon. With that screen separating the room into two halves, no living thingcould cross it without either such muscular paralysis as Thorn hadjust experienced, or death. Coils in the floor induced alternatingcurrents in the flesh itself, very like those currents used forsupposed medical effects in "medical batteries, " and "shockers. "

"Be calm!" said Kreynborg, chuckling. "I am pleased to haff company. This is der loneliest spot in der Rockies. It was chosen for thatreason. But I shall be here for maybe months, and now I shall not belonely. We of der Com-Pubs haff scientific resources such as yourfools haff nefer dreamed of, but there is no scientific substitute fora pretty woman. "

He turned again to the writing device. It clicked half a dozen timesmore, and he stopped. A strip of paper came out of it. He inserted itinto the slot of another mechanism and switched on a standard G. C. Phone as the paper began to feed. In seconds the room was filled withunearthly hoots and wails and whistles. They came from the device intowhich the paper was feeding, and they poured into the G. C. Transmitter. They went on for nearly a minute, and ceased. Kreynborgshut off the transmitter. 

"My code, " he observed comfortably, "gifing der good news toStalingrad. Everything is going along beautifully. I roused der fairSylva and kissed her a few times to make her scream into a record, andI interpolated her screamings into der last code transmission. Yourwise men think der Martians haff vivisected her. They areconcentrating der entire fighting force of der United Nations outsideder dome of force. And all for a few kisses!"

 * * * * *

Thorn was white with rage. His eyes burned with a terrible fury. Hishands shook. Kreynborg chuckled again. 

"Oh, she is unharmed--so far. I haff not much time now. Presently dertwo of you will while away der time. But not now. "

He switched on the G. C. Receiver and the room filled with a multitudeof messages. Thorn sat beside Sylva, watching, watching, watching, while invisible machinery whined softly and Kreynborg listenedintently to the crisp, curt official reports that came through on theFighting Force band. Three combat-squadrons were on the spot now;One, Three and Eight. Four more were coming at fast cruisingspeed--four hundred miles an hour. One combat-squadron of the wholefleet alone would be left to cope with all other emergencies thatmight arise. .. . A television screen lighted up and Thorn could seewhere the lenses on the bulbous tower showed the air all about filledwith fighting-planes, hovering about the dome of force like mothsbeating their wings against a screen. The strongest fighting-force inthe world, helpless against a field of electric energy!

"It is amusing, " chuckled Kreynborg, looking at the screencomplacently. "Der dome of force is a new infention. It is aheterodyning of one frequency upon another at a predetermineddistance. It has all der properties of matter except mass and a limitof strength. There is no limit to its strength! But it cannot be madeexcept in a sphere, so at first it seemed only a defensif weapon. Withit, we could defy der United Nations to attack us. But we wished to domore. So I proposed a plan, and I haff der honor of carrying it out. If I fail, Krassin disavows me. But I shall not fail, and I shall endas Commissar for der continent of North America!"

 * * * * *

He looked wisely at Thorn, who sat motionless. 

"You keep quiet, eh, and wait for me to say something indiscreet?Ferry well, I tell you. We are in a sort of gold-fish globe ofelectric force. Your air fleet cannot break in. You know that! Also, if they were in they could not break out again. So I wait, ferypatiently pretending to be a Martian until all your Fighting Force hasgathered around in readiness to fight me. But I shall not fight. Ishall simply make a new and larger gold-fish globe, outside of thisone. And then I go out and make faces at der Fighting Force of derUnited Nations imprisoned between der two of them--and then derCom-Pub fleet comes ofer!"

He stood up and put his hand on a door-knob. 

"Is it not pretty?" he asked blandly. "In two weeks der air fleet willbegin to starfe. In three, there will be cannibalism, unless derCom-Pubs accept der surrender. Imagine. .. . " He laughed. "But do notfear, my friendt! I haff profisions for a year. If you are amusing, Ifeed you. In any case I exchange food for kisses with der charmingSylva. It will be amusing to change her from a woman who screams as Ikiss her, to one who weeps for joy. If I do not haff to kill you, youshall witness it!"

He vanished through a doorway on the farther side of the room. Instantly Thorn was on his feet. The dead slumber in which Sylva wassunk was wholly familiar. Electric anesthesia, used not only forsurgery, but to enforce complete rest at any chosen moment. He draggedher from that couch to his own. He saw her stir, and her eyes wereinstantly wide with terror. But Thorn was tearing the couch to pieces. Cover, pneumatic mattress. .. . He ripped out a loosely-fittingframe-piece of steel. 

"Quick, now, " he said in a low tone, "I'm going to short theinduction-screen. We'll get across it. Then--out the door!"

 * * * * *

She struggled to her feet, terrified, but instantly game. Thorn slidthe rod of metal across the stretch of flooring he had previously beenunable to cross. The induced currents in the rod amounted to ashort-circuit of the field. The rod grew hot and its paint blisteredsmokily. Thorn leaped across with Sylva in his wake. He pointed to thedoor, and she fled through it. He seized a chair, crashed itfrenziedly into the television screen, and had switched on the G. C. Phone when there was a roar of fury from Kreynborg. Instantly therewas the spitting sound of a pocket-gun and in the red room the rackingcrash of a hexynitrate pellet. Nothing can stand the instant crash ofhexynitrate. Its concussion-wave is a single pulsation of the air. Thecellate diaphragm of the G. C. Transmitter tore across from itsviolence and Thorn cursed bitterly. There was no way, now, ofsignaling. .. . 

A second racking crash as a second pellet flashed its tiny greenflame. Kreynborg was using a pocket-gun, one of those small terribleweapons which shoot a projectile barely larger than the graphite of alead pencil, but loaded with a fraction of a milligram of hexynitrate. Two hundred charges would feed automatically into the bore as thetrigger was pressed. 

Thorn gazed desperately about for weapons. There was nothing in sight. To gain the outside world he had to pass before the doorway throughwhich the bullets had come. .. . And suddenly Thorn seized thecode-writer and the device which transmitted that code as a series ofunearthly noises which the world was taking for Martian speech. Heswung the two machines before the door in a temporary barrier. Whatever else Kreynborg might be willing to destroy, he would notshoot into them!

Thorn leaped madly past the door as Kreynborg roared with rage again. He paused only to hurl a chair at the two essential machines, and asthey dented and toppled, he fled through the door and away. 

 * * * * *

Sylva peered anxiously at him from behind a huge boulder. He racedtoward her, expecting every second to hear the spitting of Kreynborg'spocket-gun. With the continuous-fire stud down, the little gun wouldshoot itself empty in forty-five seconds, during which time Kreynborgcould play it upon him like a hose that spouted death. But Thorn haddone the hundred yards in eleven seconds, years before. He betteredhis record now. The first of the little green flashes came when he wasno more than ten yards from the boulder which sheltered Sylva. Thetiny pellet had missed him by inches. Three more, and he was safe frompursuit. 

"But we've got to get away!" he panted. "He can shoot gas here and getus again! He can cover four hundred yards with gas, and more than thatwith guns. "

They fled down a tiny water-course, midget figures in an infinity ofearth and sky, scurrying frenziedly from a red slug-like thing thatlay askew in a mountain valley. Far away and high above hung thewar-planes of the United Nations. Big ones and little ones, hoveringin hundreds about the outside of the dome of force they could neitherpenetrate nor understand. 

A quarter of a mile. Half a mile. There was no sign from Kreynborg orthe rocket-ship. Thorn panted. 

"He can't reach us with gas, now, and it looks like he doesn't dareuse a gun. They'd know he wasn't a Martian. At night he'll use thathelicopter, though. If we can only make those ships see us. .. . "

 * * * * *

They toiled on. The sun was already slanting down toward the westernsky. At four--by the sun--Thorn could point to a huge air-dreadnaughthanging by lazily revolving gyros barely two miles away. He wavedwildly, frantically, but the big ship drifted on, unseeing. TheFighting Force was no longer looking for Thorn and Sylva. They hadbeen carried into the rocket-ship fourteen hours and more before. Sylva's screaming had been broadcast with the weird hoots andwhistles the United Nations believed to be the language ofinter-planetary invaders. The United Nations believed them dead. Now awatch was being kept on the rocket-ship, to be sure, but it wasbecoming a matter-of-fact sort of vigilance, pending the arrival ofthe rest of the Fighting Force and the cracking of the dome of forceby the scientists who worked on it night and day. 

On level ground, Thorn and Sylva would have reached the edge of thedome in an hour. Here they had to climb up steep hillsides and downprecipitous slopes. Four times they halted to make frantic efforts toattract the attention of some nearby ship. 

It was six when they came upon the rim. There was no indication of itsexistence save that three hundred yards from them boughs waved andleaves quivered in a breeze. Inside the dome the air was utterlystill. 

"There it is!" panted Thorn. 

Wearied and worn out as they were, they hurried forward, and abruptlythere was something which impeded their movements. They could reachtheir hands into the impalpable barrier. For one foot, two, or eventhree. But an intolerable pressure thrust them back. Thorn seized asapling and ran at the barrier as if with a spear. It went five feetinto the invisible resistance and stopped, shot back out as if flungback by a jet of compressed air. 

"He told the truth, " groaned Thorn. "We can't get out!"

 * * * * *

Long shadows were already reaching out from the mountains. Darknessbegan to creep upward among the valleys. Far, far away a compact darkcloud appeared, a combat-squadron. It swept toward the dome anddissociated into a myriad specks which were aircraft. The fliersalready swirling about the invisible dome drew aside to leave aquadrant clear, and Combat-Squadron Seven merged with the rest, makingthe pattern of dancing specks markedly denser. 

"With a fire, " said Thorn desperately, "they'll come! Of course! ButKreynborg took my lighter!"

Sylva said hopefully:

"Don't you know some way? Rubbing sticks together?"

"I don't, " admitted Thorn grimly, "but I've got to try to invent one. While I'm at it, you watch for fliers. "

He searched for dry wood. He rubbed sticks together. They grew warm, but not enough to smoke, much less to catch. He muttered, "A drill, that's the idea. All the friction in one spot. " He tugged at the ringunder his lapel and the parachute fastened into his uniform collarshot out in a billowing mass of gossamer silk, flung out by thepowerful elastics designed to make its opening certain. Savagely, hetore at the shrouds and had a stout cord. He made a drill and revolvedit as fast as he could with the cord. .. . 

A second dark cloud swept forward in the gathering dusk and mergedinto the mass of fliers about the dome. Five minutes later, a third. Dense as the air-traffic was, riding-lights were necessary. They beganto appear in the deepening twilight. It seemed as if all the sky werealight with fireflies, whirling and swirling and fluttering here andthere. But then the fire-drill began to emit a tiny wisp of smoke. Thorn worked furiously. Then a tiny flickering flame appeared, whichhe nursed with a desperate solicitude. Then a larger flame. Then aroaring blaze! It could not be missed! A fire within the dome couldnot fail to be noted and examined instantly!

 * * * * *

A searchlight beam fell upon them, illuminating him in a pitilessglare. Thorn waved his arms frantically. He had nothing with which tosignal save his body. He flung his arms wide, and up, and wide again, in an improvised adaption of the telegraphic alphabet togesticulation. He sent the watch call over and over again. .. . 

A little cloud of riding-lights swept toward the dome from an infinitedistance away. Darkness was falling so swiftly that they were stillmerely specks of light as they swept up to and seemed to melt into theswirling, swooping mass of fliers about the dome. .. . 

Cold sweat was standing out on Thorn's face, despite the violence ofhis exertions. He was even praying a little. .. . And suddenly thesearchlight beam flickered a welcome answer:

"W-e u-n-d-e-r-s-t-a-n-d. R-e-p-o-r-t. "

Thorn flung his arms about madly, sending:

"G-e-t a-w-a-y q-u-i-c-k. C-o-m P-u-b-s h-e-r-e. W-i-l-l m-a-k-eo-t-h-e-r d-o-m-e o-u-t-s-i-d-e t-o t-r-a-p y-o-u. "

The searchlight beam upon him flickered an acknowledgment. He knewwhat was happening after that. The G. C. Phones would flash the warningto every ship, and every ship would dash madly for safety. .. . Asudden, concerted quiver seemed to go over the whirling maze of lightsaloft. A swift, simultaneous movement of every ship in flight. Thornbreathed an agonized prayer. .. . 

There was a flash of blue light. For one fractional part of a secondthe stars and skies were blotted out. There was a dome of flame abovehim and all about the world, of bright blue flame which instantlywas--and instantly was not!

Then there was a ghastly blast of green. Hexynitrate going off. Inthis glare were silhouetted a myriad motes in flight. But there was nonoise. A second flare. .. . And then Thorn Hard, groaning, saw flashafter flash after flash of green. Monster explosions. Colossalexplosions. Terrific detonations which were utterly soundless, as theships of the Fighting Force, in flight from the menace of which Thornhad warned them, crashed into an invisible barrier and explodedwithout cracking it. 

 * * * * *

It was August 24th, 2037. For three days, now, seven of the eightgreat combat-squadrons of the United Nations Fighting Forces had beenprisoners inside a monstrous transparent dome of force. There was afinancial panic of unprecedented proportions in the great financialdistricts of New York and London and Paris. Martial law was in forcein Chicago, in Prague, in Madrid, and in Buenos Aires. The Com-Pubswere preparing an ultimatum to be delivered to the government of theUnited Nations. Thorn and Sylva were hunted fugitives within the innerdome of force, which protected the red rocket-ship from the sevencombat squadrons it had imprisoned. Newspaper vendor-units wereshrieking, "Air Fleet Still Trapped!" and a prominent Americanpolitician was promising his constituents that if a foreign nationdared invade the sacred territories of the United Nations, a millionembattled private planes would take the air. And he seemed not eventrying to be humorous! Scientists were wringing their hands in utterhelplessness before the incredible resistance of the dome. It had beendetermined that the dome was a force-field which caused particlescharged with positive electricity to attempt to move in a right-handdirection about the source of the field, and particles charged withnegative electricity to attempt to move in a left-hand direction. Theresult was that any effort to thrust an external object into the fieldof force was an attempt to tear the negatively charged electrons ofevery atom of that substance, free from the positively charged protonsof nuclei. An object could only be passed through the field of forceif it ceased to exist as matter--which was not an especially helpfuldiscovery. And--Thorn Hard and Sylva were still hunted fugitivesinside the inner dome. 

 * * * * *

The sun was an hour high when the helicopter appeared to hunt for themby day. After the first time they had never dared light a fire, because Kreynborg in the helicopter searched the hills for a glow oflight. But this day he came searching for them by day. Thorn hadspeared a fish for Sylva with a stick he had sharpened by rubbing iton a crumbling rock. He was working discouragedly on a littlecontrivance made out of a forked stick and the elastic from hisparachute-pack. He was haggard and worn and desperate. Sylva wasbeginning to look like a hunted wild thing. 

Two hundred yards from them the most formidable fighting force theworld had ever seen littered the earth with gossamer-seeming cellatewings and streamlined bodies at all angles to each other. And it wascompletely useless. The least of the weapons of the air-fleet wouldhave been a godsend to Thorn and Sylva. To have had one ship, even thesmallest, where they were would have been a godsend to the fleet. Buttwo hundred yards, with the dome of force between, made the fleet justexactly as much protection for Sylva as if it had been a million milesaway. 

The droning hum of the helicopter came across the broken ground. Nowlouder, now momentarily muted, its moments of loudness grew steadilymore strong. It was coming nearer. Thorn gripped his spear in aninstinctive, utterly futile gesture of defense. Sylva touched hishand. 

"We'd better hide. "

They hid. Thick brush concealed them utterly. The helicopter wentslowly overhead, and they saw Kreynborg gazing down at the earth belowhim. Nearly overhead he paused. And suddenly Thorn groaned under hisbreath. 

"It's the flagship!" he whispered hoarsely to Sylva. "Oh, what foolswe were! The flagship! He knows the General would have brought it toearth opposite us, to question us!"

 * * * * *

The flagship was nearly opposite. To find the flagship was more orless to find where Thorn and Sylva hid. But they had not realized ituntil now. 

The speaker in the helicopter boomed above their heads. 

"Ah, my friends! I think you hear me. Answer me. I haff an offer tomake. "

Shivering, Sylva pressed close to Thorn. 

"Der Com-Pub fleet is on der way, " said Kreynborg, chuckling. "Sefen-eights of der United Nations fleet is just outside. You haffobserved it. In six hours der Com-Pub fleet begins der conquest of dercountry and der execution of persons most antagonistic to our regime. But I haff still weary weeks of keeping der air fleet prisoner, untilits personnel iss too weak from starfation to offer resistance to oursoldiers. So I make der offer. Come and while away der weary hours forme, and I except you both from der executions I shall findt itnecessary to decree. Refuse, and I get you anyhow, and you willregret your refusal fery much. "

Thorn's teeth ground together. Sylva pressed close to him. 

"Don't let him get me, Thorn, " she panted hysterically. "Don't let himget me. .. . "

 * * * * *

The droning, monotonous hum of the helicopter over their headscontinued. The little flying-machine was motionless. The air wasstill. There was no other sound in the world. 

Silence, save for the droning hum of the helicopter. Then somethingdropped. It went off with an inadequate sort of an explosion and acloud of misty white vapor reared upward on a hillside and began tosettle slowly, spreading out. .. . The helicopter moved and other thingsdropped, making a pattern. .. . 

"The air's still, " said Thorn quite grimly. "That stuff seems to beheavier than air. It's flowing downhill, toward the dome-wall. It willbe here in five minutes. We've got to move. "

Sylva seemed to be stricken with terror. He helped her to her feet. They began to move toward higher ground. They moved with infinitecaution. In the utter silence of this inner dome, even the rustling ofa leaf might betray them. 

It was the presence of the air fleet within clear view that made thething so horrible. The defenders of a nation were watching the enemyof a nation, and they were helpless to offer battle. The helicopterhummed and droned, and Kreynborg grinned and searched the earth belowhim for a sign of the man and girl who had been the only danger to hisplan and now were unarmed fugitives. And there were fourair-dreadnaughts in plain sight and five thousand men watching, andKreynborg hunted, for sport, a comrade of the five thousand men and awoman every one of them would have risked or sacrificed his life toprotect. 

He seemed certain that they were below him. Presently he droppedanother gas-bomb, and another. And then Sylva stumbled and caught atsomething, and there was a crashing sound as a sapling wavered in hergrasp. .. . And Thorn picked her up and fled madly. But billowing whitevapor spouted upward before him. He dodged it, and the helicopter wasjust overhead and more smoke spouted, and more, and more. .. . They werehemmed in, and Sylva clung close to Thorn and sobbed. .. . 

 * * * * *

Five thousand men, in a thousand grounded aircraft, shouted cursesthat made no sound. They waved weapons that were utterly futile. Theywere as impotent as so many ghosts. Their voices made not even thehalf-heard whisper one may attribute to a phantom. 

The fog-vapor closed over Thorn and Sylva as Kreynborg grinnedmockingly at the raging men without the dome of force. He swept thehelicopter to a position above the last view of Thorn and Sylva, andthe downward-beating screws swept away the foggy gas. Thorn and Sylvalay motionless, though Thorn had instinctively placed himself in aposition of defense above her. 

The Fighting Force of the United Nations watched, raging, whileKreynborg descended deliberately into the area the helicopter-screwskept clear. While he searched Thorn's pockets reflectively and foundnothing more deadly than small pebbles which might strike sparks, anda small forked stick. While he grinned mockingly at the raging armedmen and made triumphant gesticulations before carrying Sylva's limpfigure to the helicopter. While the little ship rose and swept awaytoward the rocket-plane. 

It descended and was lost to view. Thorn lay motionless on the earth. Seven-eighths of the fighting force of the United Nations wasimprisoned within the space between two domes of force no matter couldpenetrate. A ring two miles across and ten miles in outer diameterheld the whole fleet of the United Nations paralyzed. 

There was sheer panic through the Americas and Europe and the fewoutlying possessions of the United Nations. .. . And it was at thistime, with a great fleet already half-way across the Pacific, that theCom-Pubs declared war in a fine gesture of ironic politeness. It waswithin half an hour of this time that the Seventh Combat Squadron--theonly one left unimprisoned--dived down from fifty thousand feet intothe middle of the Com-Pub fleet and went out of existence in twentyminutes of such carnage as is still stuff for epics. 

The Seventh Squadron died, but with it died not less than three timesas many of the foe. And then the Com-Pub fleet came on. Most of theoriginal force remained; surely enough to devastate an undefendednation, to shatter its cities and butcher its people; to slaughter itsmen and enslave its women and leave a shambles and smoking ash-heapswhere the very backbone of resistance to the red flag had been. 

 * * * * *

It was twenty minutes before Thorn Hard stirred. His lungs seemed onfire. His limbs seemed lead. His head reeled and rocked. He staggeredto his feet and stood there swaying dully. A vivid light, brighterthan the sunshine, played upon him from the flagship of the fleetwhich now was helpless to defend its nation. Thorn's befogged brainstirred dazedly as the message came. 

"Com-Pub fleet on way. Seventh Combat-Squadron wiped out. Nationdefenseless. You are only hope. For God's sake try something. Anything. "

Thorn roused himself by a terrific effort. He managed to ask aquestion by exhausted gestures in the Watch visual alphabet. 

"Kreynborg took her to rocket-ship, " came the answer. "She recoveredconsciousness before being carried inside. "

And Thorn, reeling on his feet and unarmed and alone, turned and wentstaggering up a hillside toward the rocket-ship's position. He couldonly expect to be killed. He could not even hope for anything morethan to ensure that Sylva, also, die mercifully. Behind him he left anunarmed nation awaiting devastation, with a mighty air fleet speedingtoward it at six hundred miles an hour. 

As he went, though, some strength came to him. The fury of his toilforced him to breathe deeply, cleansing his lungs of the stupefyinggas which, because it was visible as a vapor, had been carried in therocket-ship. A visible gas was, of course, more consistent with theearly pretense that the rocket-ship bore invaders from another planet. And Thorn became drenched with sweat, which aided in the excretion ofthe poisonous stuff. His brain cleared, and he recognized despair anddiscounted it and began to plan grimly to make the most of aninfinitesimal chance. The chance was simply that Kreynborg hadransacked his pockets and ignored a little forked stick. 

 * * * * *

Scrambling up a steep hillside with his face hardened into granite, Thorn drew that from his pocket again. Crossing a hill-top, hestripped off his coat. 

He traveled at the highest speed he could maintain, though it seemedpainfully deliberate. An hour after he had started, he was picking upsmall round pebbles wherever he saw them in his path. By the time thetall, bulbous tower was in sight he had picked up probably sixty suchpebbles, but no more than ten of them remained in his pockets. They, though, were smooth and round and even, perhaps an inch in diameter, and all very nearly the same size. And he carried a club in his hand. 

He went down the last slope openly. The television lenses on the towerwould have picked him out in any case, if Kreynborg had repaired thescreen. He went boldly up to the rocket-ship. 

"Kreynborg!" he called. "Kreynborg!"

He felt himself being surveyed. A door came open. Kreynborg stoodchuckling at him with a pocket-gun in his hand. 

"Ha! Just in time, my friend! I haff been fery busy. Der Com-Pub fleetis just due to pass in refiew abofe der welcoming United Nationscombat-squadrons. I haff been gifing them last-minute information andassurance that der domes of force are solid and can hold forefer. Ihaff a few minutes to spare, which I had intended to defote to derfair Sylva. But--what do you wish?"

"I'm offering you a bribe, " said Thorn, his face a mask. "A billiondollars and immunity to cut off the outer dome of force. "

Kreynborg grinned at him. 

"It is too late. Besides being a traitor, I would be assassinatedinstantly. Also, I shall be Commissar for North America anyhow. "

"Two billion, " said Thorn without expression. 

"No, " said Kreynborg amusedly. "Throw away der club. I shall amusemyself with you, Thorn Hardt. You shall watch der progress of romancebetween me and Sylva. Throw away der club!"

The pocket-gun came up. Thorn threw away the club. 

"What do you want, if two billion's not enough?"

"Amusement, " said Kreynborg jovially. "I shall be bored in this innerdome, waiting for der air fleet to starfe. I wish amusement. And Ishall get it. Come inside!"

 * * * * *

He backed away from the door, his gun trained on Thorn. And Thorn sawthat the continuous-fire stud was down. He walked composedly into thered room in which he had once awakened. Sylva gave a little choked cryat sight of him. She was standing, desperately defiant, on the otherside of the induction-screen area on the floor. There was a scorchedplace on the floor where Thorn had shorted that screen and the bar ofmetal had grown red-hot. Kreynborg threw the switch and motioned Thornto her. 

"I do not bother to search you for weapons, " he said dryly. "I did itso short a time ago. And you had only a club. .. . "

Thorn walked stiffly beside Sylva. She put out a shaking hand andtouched him. Kreynborg threw the switch back again. 

"Der screen is on, " he chuckled. "Console each other, children. I amglad you came, Thorn Hardt. We watch der grand refiew of der Com-Pubfleet. Then I turn a little infention of mine upon you. It is aheat-ray of fery limited range. It will be my method of wooing derfair Sylva. When she sees you in torment, she kisses me sweetly forder prifilege of stopping der heat-ray. I count upon you, my friend, to plead with her to grant me der most extrafagant of concessions, when der heat-ray is searing der flesh from your bones. I feel thatshe is soft-hearted enough to oblige you. Yes?"

He touched a button and the repaired television-screen lighted up. All the dome of mountains and sky was visible in it. There weredancing motes in sight, which were aircraft. 

"I haff remofed all metal-work from that side of der room, " addedKreynborg comfortably, "so I can dare to turn my back. You cannotshort der induction-screen again. That was clefer. But you face ascientist, Thorn Hardt. You haff lost. "

A sudden surge of flying craft appeared on the television screen. Thegrounded fleet of the United Nations was taking to the air again. Inthe narrow, two-mile strip between the two domes of force it swirledup and up. .. . Kreynborg frowned. 

"Now, what is der idea of that?" he demanded. He moved closer to thescreen. The pocket-gun was left behind, five feet from hisfinger-tips. "Thorn Hardt, you will explain it!"

"They hope, " said Thorn grimly, "your fleet can make gaps in the dometo shoot through. If so, they'll go out through those gaps and fight. "

"Foolish!" said Kreynborg blandly. "Der only weapon we haff to use isder normal metabolism of der human system. Hunger!"

 * * * * *

Thorn reached into his pocket. Kreynborg was regarding the screenabsorbedly. Through the haze of flying dots which was the UnitedNations fleet, a darkening spot to westward became visible. It drewnearer and grew larger. It was dense. It was huge. It was deadly. Itwas the Com-Pub battle-fleet, nearly equal to the imprisoned ships innumber. It swept up to view its helpless enemy. It came close, soevery man could see their only possible antagonists rendered impotent. 

Such a maneuver was really necessary, when you think of it. TheCom-Pub fleet had encountered one combat-squadron of the UnitedNations fleet, and that one squadron, dying, had carried down threetimes its number of enemies. It was necessary to show the Com-Pubpersonnel the rest of their enemies imprisoned, in order to heartenthem for the butchery of civilians before them. 

Kreynborg guffawed as the Com-Pub fleet made its mocking circuit ofthe invisible dome. And Thorn raised his head. 

"Kreynborg!" he said grimly. "Look!"

There was something in his tone which made Kreynborg turn. And Thornheld a little forked stick in his hand. 

"Turn off the induction-screen, or I kill you!"

Kreynborg looked at him and chuckled. 

"It is bluff, my friend, " he said dryly. "I haff seen many weapons. Iam a scientist! You play der game of poker. You try a bluff! But Ianswer you with der heat-ray!"

He moved his great bulk, and Thorn released his left hand. There was asudden crack on Kreynborg's side of the room. A pebble a little overan inch in diameter fell to the floor. Kreynborg wavered, and toppledand fell. Three times more, his face merciless, Thorn drew back hisarm, and three times Kreynborg's head jerked slightly. Then Thornfaced the panel on which the induction-screen switch was placed. Several times he thrust his hand through the screen and abruptly drewit back with pain, in an attempt to throw the switch. At last he wassuccessful, and now he walked calmly across the room and bent over themotionless Kreynborg. 

"Skull fractured, " he said grimly. "All right, Sylva. "

 * * * * *

He went through the narrow doorway beyond, picking up the pocket-gunas he went. There was a noise of whining machinery. Now Thorn wasemptying pellets into the mechanism that controlled the dome of force. There was a crashing of glass. It stopped. There were blows andthumpings. That noise stopped too. 

Thorn came back, his eyes glowing. He flung open the outer door of therocket-ship, and Sylva went to him. 

He pointed. 

Far away, the Fighting Force of the United Nations was swirlingupward. Like smoke from a campfire or winged ants from a tree-stump, they went up in a colossal, twisting spiral. Beyond the domes andabove them. The domes existed no longer. Up and up, and up. .. . Andthen they swooped down upon the suddenly fleeing enemy. Vengefully, savagely, with all the fury of men avenging not only what they havesuffered, but also what they have feared, the combat-squadrons of theUnited Nations fell upon the invaders. Green hexynitrate explosionslighted up the sky. Ear-cracking detonations reverberated among themountains. There was battle there, and death and carnage and utterdestruction. The roar of combat filled the universe. 

Thorn closed the door and looked down at Kreynborg, who breathedstentorously, his mouth foolishly open. 

"Our men will be back for us, " he said shortly. "We needn't worry. "Then he said, "Huh! He called himself a scientist, and he didn't knowa sling-shot when he saw one!"

But then Thorn Hard dropped a weapon made of a forked stick and strongelastic from his chute-pack, and caught Sylva hungrily in his arms. 

 * * * * *