One man fell screaming out of the big skyhook copter, but someone remained inside, for it lurched and dipped and roared crazily across the field in as ragged a take-off as I ever saw, until its pilot got it under control. It bobbed over the skirmish line under fire, but returning the fire as whatever few persons were inside it leaned out and strafed the expediters. Then the skyhook itself came under attack as the patrol copters swooped in. The big ship staggered toward the nearest of them. It must have been intentional: We could see the faint flare of muzzle-blast as the two copters fired on each other; they closed, and there was a brutal rending noise as they collided. They were barely a hundred feet in the air; they crashed in a breath, and flames spread out from the wreckage. * * * * * And Slovetski's resources still had not run out. There was a roar and a screech of metal, and a one-man cobra tank slithered out of one of the buildings and came rapidly across the field toward the expediters. Gogarty, beside me, was sobbing with fear; that little tank carried self-loading rockets. It blasted a tiny shrine into rubble, spun and came directly toward us. We ran. I didn't even see the second expediter aircraft come whirling in and put the cobra tank out of action with its heavy weapons. I heard the firing, but it was swallowed up in a louder screaming roar. Gogarty stared at me from the drainage trench we had flung ourselves into. We both leaped up and ran back toward the open field. There was an explosion as we got there--the fake "olive-oil" truck, now twenty yards from the bomb, had gone up in a violent blast. But we hardly noticed. For at the base of the bomb itself red-purple fire was billowing out. It screamed and howled and changed color to a blinding blue as the ugly squat shape danced and jiggled. The roar screamed up from a bull-bass to a shrieking coloratura and beyond as the bomb lifted and gained speed and, in the blink of an eye, was gone. I hardly noticed that the sound of gunfire died raggedly away. We were not the only ones staring unbelievingly at the sky where that deadly shape had disappeared. Of the scores of men on both sides in that area, not a single eye was anywhere else. The bomb had been fueled; we were too late. Its servitors, perhaps at the cost of their own lives, had torched it off. It was on its way. The cobalt bomb--the single weapon that could poison the world and wipe out the human race--was on its way. XIII What can you do after the end? What becomes of any plot or plan, when an indigo-gleaming missile sprays murder into the sky and puts a period to planning? I do not think there ever was a battlefield as abruptly quiet as that square in old Pompeii. Once the bomb had gone, there was not a sound. The men who had been firing on each other were standing still, jaws hanging, eyes on the sky.