As the bolster-truck moved silently toward Headquarters, a hundred-yard section of the wall collapsed. There was an upsurging of dust. There was a rumbling of falling, hardened wall. The truck's driver turned white. A civilian beside the road faced the wall and wrung his hands, and stood waiting to feel the ground under his feet begin to sweep smoothly toward the here-distant sea. A post held up a traffic signal some twenty yards from the gate. It leaned slowly. At a forty-five-degree tilt it checked and hung stationary. Fifty yards from the gate, a new crack appeared across the road. But nothing more happened. Nothing. Yet one could not be sure that some critical point had not been passed, so that from now on there would be a gradual rise in the creeping of the soil toward the ocean. Barnes caught his breath. "That--makes one feel queer," he said unsteadily. "A ... shock like that wall falling could start everything off!" Hardwick said nothing at all. It had occurred to him that there was no irrigation of the Survey area. He frowned very thoughtfully--even worriedly, as the truck went inside the Headquarters gate and rolled smoothly on over a winding road through definitely parklike surroundings. * * * * * It stopped before the building which was the Sector Chief's own headquarters in Headquarters. A large brown dog dozed peacefully on the plastic-tiled landing at the top of half a dozen steps. When Hardwick got out of the truck the dog got up with a leisurely air. When Hardwick ascended the steps, with Barnes following him, the dog came forward with a sort of stately courtesy to do the honors. Hardwick said: "Nice dog, that." He went inside. The dog sedately followed. The interior of the building was singularly empty. There was a sort of resonant silence until somewhere a telewriter began to click. "Come along," said Hardwick. "The Sector Chief's office is over this way." Young Barnes followed uncomfortably. "It seems odd there's no one around. No secretaries, no sentries, nobody at all." "Why should there be?" asked Hardwick in surprise. "The guards at the gate keep civilians out. And nobody in the Service will bother the Chief without reason. At least, not more than once!" But across a glistening, empty floor there ran an ominous crack. They went down a corridor. Voices sounded, and Hardwick tracked them, with the paws of the dog clicking on the floor behind him. He led the way into a spacious, comfortably nondescript room with high windows--doors, really--that opened on green lawn outside. The Sector Chief, Sandringham, leaned placidly back in a chair, smoking. Werner, the other summoned Senior Officer, sat bolt upright in a chair facing him. Sandringham waved a hand cordially to Hardwick. "Back so soon? You're ahead of schedule on all counts! Here's Werner, back from looking at the fuel-store situation."