As the beetle's flank cleared the corner of the digging blade with inches to spare, Dworn's gun turret passed in line with the space between the blade and the caterpillar's treads, and he jabbed the firing button. The explosion wreathed the monster's forward half in smoke and dust, and into that cloud it tilted forward, teetered ponderously and then slid headlong to the bottom of the wash as the loosened bank gave way conclusively under its great weight.
Dworn looked back from the hill crest to see it still floundering, treads furiously churning sand, struggling to fight clear of the avalanche it had carried with it. The beetle laughed full-throatedly, without rancor. This hadn't been the first nor the tightest corner he'd been in during the dangerous course of his wanderyear; and in that hard school of life you learned not to worry about danger already past.
At another time, he might have returned to the battle in hope of capturing the additional supplies the caterpillar carried and—still more valuable booty—the chart it would have, showing the location of its other caches. But now he was in a hurry—this refueling foray had cost him a couple of hours, and the moon was already high.
So he slipped quietly away over the ridge and set his course to the east.
Beyond the hilly land, the terrain ironed out into level alkali flats where a vanished lake had been in the long-gone days when the earth was fertile. There he opened the throttle wide. The plain, white in the moonlight, rolled under the racing wheels at ninety and a hundred miles an hour; air whistled over the carapace....
Impatience surged up in Dworn once more. Eagerly he pictured his forthcoming reunion with his native horde—and with Yold, his father, chief of the horde.
Countless times in the long wanderyear—in moments when death loomed nearer than it had in the brush just past, and he despaired of surviving his testing, or in other moments, yet harder to bear, when the immensity of of the desert earth seemed about to swallow him up in his loneliness—he had grasped at that vision now soon to be real: he, Dworn, stood before the assembled horde, the year of his proving triumphantly completed, and he received before them all the proud, laconic commendation of the chief, his father.
Hungrily he scanned the horizon ahead, saw with leaping heart that it was no longer flat. Along it a black line rose, and grew ragged as it came nearer, and became an endless line of cliffs, marching straight north and south as far as the eye could see.... The Barrier!
Dworn recognized familiar landmarks, and altered his direction a little so as to be heading directly for the year's-end rendezvous. He knew, from childhood memories even, the outline of that vast stone rampart as it appeared by moonlight. Every year the Barrier formed the eastern limit of the beetles' annual migration, as naturally as the shore of the sea was its westward terminus. So it had been for a thousand years or more, as far back as the oldest traditions reached: generation after generation, hunting, foraging, and fighting—from the Barrier to the ocean, from the ocean to the Barrier.