We fought that wall for days and nights on end, as a mob, in shifts, and singly. We got nowhere. There were times when the sand inside the dome looked as if a huge animal had been rooting, or a crowd digging for treasure. But when we stopped for a few moments to rest we could hear the sand whispering with glee as it slid back into the pits we had dug--leveling off the area again. We managed in some places to get down ten feet or so into the sand, and to witness a strange phenomenon. We never got under the wall, nor were we able to penetrate it anywhere, yet when sand poured back into the pits we dug--_it poured back from beyond the wall, too_, as if there were no obstruction! It poured in, apparently through the very wall we were trying to breach. Naturally we wondered, if we had been digging on the outside, trying to get in, if the sand would have poured outward into the holes, too. We all remembered how we had got into the dome so easily, yet we could find no way, shape, form or manner to get out. The Shadow Men, however, had escaped.... Yes, we studied that LCVP that had seemed to be a funnel by which the Shadow Men coalesced into one shadow and vanished, but could find no key to the means or manner of their strange escape. We were resting one afternoon, and Haggerty had just said this was the most unsatisfactory duty he had ever performed in twenty-some years of landing with the marines around the world, while Hoose suggested we ought to have a name for this nameless area, and Trumpeter Krane offered "Outpost Zero" as the most appropriate--when Preble erupted: "My God! Look!" He was pointing up through the dome. Spinning down toward us from an empty sky was a ball of something that looked like metal--or perhaps crystal. It glistened and shone in the sun. It almost hurt the eyes. Nobody said anything as that ball came closer and closer. I think we all knew what it was, though none of us had been at Hiroshima that fatal day. We saw the A-bomb disintegrate, almost lazily, directly above our dome. No one who has seen the Hiroshima pictures needs a further explanation of what we all saw. Only, this A-bomb was far more powerful than the first one. Only one nation, we all thought, could have it. Why would our own people be so intent on wiping us out? In a split second we were in the midst of the cloud, in the heart of the explosion, each one of us trying to convince himself, by pinching, that he was actually going through an A-bomb explosion--absolutely unscathed. Not even a sound came through. We were sitting in the middle of the perfect defense against the A-bomb, but we didn't know what it was or who had made it--and we couldn't get out of it! There was comfort in the knowledge that _someone_ knew, else how did it happen that the A-bomb made what would have been a direct hit on the dome if it hadn't been detonated about a thousand feet above? There was design here, all right--but _whose_?