A hatch-cover clanged shut, and another. The squabbling scavengers had finally noticed the appearance of outside compet.i.tion. The one upslope raced its engine uncertainly, swung round to face the buzzing invaders, hesitated.

The newcomers, for their part, seemed oblivious to the scavengers'

presence. Their column began dispersing. A grapple-armed machine laid hold on one of the wrecked beetles and, whining with effort, sought to drag it to leveler ground. A second, following, spat a burst of sparks and extended a gleaming arm tipped by the singing blue radiance of a cutting torch.

The first-come scavenger growled throatily and lumbered toward the interlopers, plainly taking heart from their air of harmless stupidity.

Behind it, the other scavenger came clattering up the slope to its fellow's aid.

Flame bloomed thunderously from the muzzle of the first one's forward gun. The machine with the torch was flung bodily into the air and went rolling and bouncing down the hill, wheels futilely spinning. The gun roared again, and the exploding sh.e.l.l tore open a flimsy aluminum body from nose to tail. Motors whirred frantically as the pygmies scattered before the charging behemoth. One of them darted witlessly right under the huge treads, and disappeared with a brief screech of crumpling metal.

The fight was over as quickly as it had begun. The scavenger wheeled, snorting, and fired one more shot into the dark after its routed opponents....

Dworn muttered an imprecation under his breath. No chance of frightening the scavengers off now that their blood was up and their differences forgotten; and a lone beetle could scarcely stand up to two of them in a knock down fight. To rush in now would be suicidal.

He gave up the idea of investigating the scene of disaster more closely, and backed stealthily away, keeping to the cover of the rocks. At a safe distance he began circling round, downslope.

What he could and must do now was to locate what was left of his native horde. It had numbered about fifty when he had departed for his wanderyear; a dozen, perhaps more, had died on the mountain tonight. He must seek out the survivors, and help plan retaliation against whatever enemy had dealt them this terrible blow.

Yet something else nagged at his mind, until he halted to gaze achingly once more toward the glowing embers up there, where the scavengers now clanked to and fro about their business.

Dworn recognized that what bothered him was the puzzle of the unidentified little machines that had turned up on the battlefield only to be sent packing. During his yearlong solitary struggle to survive, he had developed an extra sense or two--and in the queerly confident behavior of those buzzing strangers he had scented danger, a trap....

So it happened that he was still looking on at the moment when the trap was sprung.

A star, it seemed, fell almost vertically from the zenith, falling and expanding with the uncanny silence of flight faster than sound. The scavengers had no time to act. Dworn caught one faint glimpse of a winged shape against the sky, limned by the flashes that stabbed from it as it leveled out of its terrific dive.

One scavenger shuddered with the force of a heavy explosion somewhere within it, and subsided, smoking. The other too staggered under crippling impacts, but ground somehow into motion, spinning and sliding crazily down the gravel slope. Then, as the first attacker's shock-wave made the very earth tremble, a second and a third plunged from the black heights, and as the last one rose screeching from its swoop the whole lower face of the hillside boomed into a holocaust of flame and oily smoke. The fleeing scavenger was gone, enveloped somewhere in an acre of fiery h.e.l.l.

Dworn, two hundred yards away, felt a searing breath of heat, and with a great effort controlled the impulse to whirl round and race for opener ground. He sat still, hands cramped sweating on the beetle's controls, while the sky whistled vindictively with the flight of things that circled in search of further targets.

When, after a seeming eon, their screaming died away, he released held breath in a long sigh. He found himself trembling with reaction. Still he didn't stir. He was ransacking his memory for something he should be able to recall but which eluded him--a myth, perhaps, heard as a child beside the campfires of the horde--

The old men would know; Yold would have known. At thought of his father, the grief and fury rose up again in Dworn, and this time he knew the object of his vengeful anger. There was small doubt now in his mind that those flying machines which struck so swiftly and so murderously had been the beetles' attackers.

But he didn't know what they were. He knew, of course, about the machines called hornets, which could fly and strike at fearful speeds like that, outracing sound. But the hornets flew only in daylight, and made no trouble for the nocturnal race of beetles. These--were something else.

And more--between the deadly night-fliers and the harmless-looking aluminum crawlers he had seen, Dworn sensed some connection, some unnatured symbiosis. He had heard vague rumors about such arrangements, but had half-discounted them; any of the peoples whom he knew at first hand would have scorned to enter into alliance with an alien species.

Lastly, he realized bitterly, he didn't even know where the enemy's lair, their base on the ground, might be....

The moon stood high now. But the Barrier, close at hand now, rose like an immense black wall, folded in shadows, revealing no secrets--walling off the world the beetles knew from the unknown beyond. Involuntarily Dworn shivered. He couldn't be sure--but it seemed to him that the destroyers had come from over the Barrier and had flown back there.

He set his machine in cautious motion again and stole along, making northward and keeping close to the Barrier. It occurred to him that the beetle horde, routed and fleeing, might well have hugged the cliffs for protection against flying foes.

The going here was not easy. The terrain seemed increasingly unfamiliar though he should have known every foot of it. But--he remembered no such tumbled crags, no such great heaps of stony detritus as blocked his way and forced him into long detours....

Finally he halted to take his bearings, and, looking up, discovered what had happened. The black rampart of the Barrier was notched and broken.

Sometime in the past year, since Dworn had left this place to begin his wandering, a quarter-mile-wide section of the upper crags, hollowed and loosened by the slow working of millennial erosion, had fallen and spilled millions of tons of rock crashing and shattering onto the slopes below. Here now water would run when the rains fell, and in ten or twenty thousand years, perhaps, a river-course would have completed the breach.

Dworn wondered fleetingly whether any living thing had been here when the cliffs fell. If so, it was buried now, crumbling bone and corroding metal, under the mountain for all time to come.

He set about skirting the rockfall, still searching the ground for traces of beetle wheels. But there were very few wheel or tread marks of any description to be seen--and that was strange in itself.

Impulsively he halted again and listened, his amplifier turned up. He should have heard faroff engine-mutterings, occasional explosions from the desert to the west, where normally the predatory machines and their victims prowled and fought all night long over the sandy tracts and the desolate ridges.... But there was nothing. A silence, vast and unnatural, lay upon the wastes in the shadow of the high plateau.

He looked up again at the fallen rampart of the Barrier. The great landship had opened, as it were, a gateway to the unknown lands in the east--a gateway for what?

There was a strangeness here since last year, and the strangeness crept chillingly into Dworn's blood, made the mountain air seem thin and cold.

As he started again, he noticed yet another curious thing. He was crossing a sandy natural terrace, and the soft soil here was traversed by a row of indented marks that marched in a straight line across the open s.p.a.ce. They were scuffed depressions, such as a ricocheting projectile might have made--but oddly regular in shape and s.p.a.cing, almost, he thought fancifully, like giant footprints, ten feet apart....

Dworn was growing numbed to riddles. He shrugged impatiently and pressed the accelerator again.

He would push on northward for a few more miles, he determined, and if he still found no sign of his people, he would circle back to the south....

The moonlight shadow of the huge tilted boulder ahead was inky. But Dworn was keeping to the shadows by preference, remembering the death from above; so he cut close around the overhanging rock.

Too late to swerve, then, he saw the gleam of something stretched across his path. A metallic glint of deceptively slender strands which, as the beetle rolled headlong into them, snapped taut without breaking, sprang back and flipped the beetle clean over to fetch up against the rock with an ear-shattering bang.

Half-stunned by the suddenness of it and the violence with which he had been flung about, Dworn blurrily saw other cables settling from overhead, coiling almost like living things around his overturned machine. Then he glimpsed something else; stalking monstrously down from the unscalable crag above, its armor glimmering in the moonlight, a machine such as he had never imagined--a machine without wheels or treads, a nightmare moving on jointed steel legs that flexed and found holds for clawed steel feet with the smooth precision of well-oiled pistons. A machine that walked.

Capsized, its vulnerable underside exposed, the beetle was all but helpless. One hope remained. With wooden fingers Dworn groped for the emergency b.u.t.ton, found it--

The propellant-charge went off beneath him with a deafening roar. The beetle was hurled upward and sidewise, in an arc that should have brought it down on its wheels again--but the ensnaring cables tightened and held, and Dworn's head slammed against something inside the cabin.

The world burst apart into a shower of lights and darkness....

Dworn came awake to a pounding head and blurred light in his eyes. He moved, and sensed that he was bound.

His vision cleared. He saw that he was in a closed, half-darkened chamber--and that discovery alone made him shudder, he who as a free beetle had spent his whole life under desert skies. His feet rested on a floor of hard-packed sand, and his back, behind which his wrists were lashed together was propped uncomfortably against a wall ribbed with metal girders. The room was circular and its walls converged upward, into tangled shadows overhead; the chamber was roughly bottle-shaped.

To one side a door stood ajar, and it was thence that the light streamed, but from where he was Dworn couldn't see into the s.p.a.ce beyond.

He tried hard to collect his thoughts. When had everything stopped making sense? When he had first glimpsed the fires that were burning beetles on the mountainside, or....

The converging lines of the wall-girders led his eyes upward. The shadows overhead resolved themselves as he studied them, and Dworn's heart pounded as he commenced to understand what manner of place he was in. The roof of the bottle-shaped chamber--he was sure it must be underground--was no roof, but was the underside of a great machine complex with gear-housings and levers connected with the six powerful metal legs radiating from it, their cleated feet resting on a shelf that encircled the bottle-neck. It squatted there, motionless above him, sealing the entrance to its burrow....

Trapped. For some reason he couldn't guess at, he had been taken alive--his human body, at least; he didn't know what had become of the rest of him, the machine that was part and parcel of him too.

The light suddenly brightened. The door at one side was swinging open.

Dworn blinked at the glare from the lighted room beyond. Against it a figure stood in silhouette, and he saw that it was a woman.

She was slender, not very tall, and her hair was jet-black, a striking frame for a startlingly pale face. Here beneath the earth she must not get much sun.... In that white face her lips were shockingly red, the color of fresh blood. And the nails of her slim white fingers were crimson claws. After a moment, he realized that both must be painted--a strange thing to him, for there was no such practice among beetle women.