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?