The Guide aimed quickly and pressed the trigger of the ultrasonic stunner. The pistol dropped soundlessly on the thick-piled rug; the man in uniform slumped in an inert heap. The Guide sprang to his feet and rounded the desk, crossing to and bending over the intruder. Why, this was the dream that had plagued him through the years. But it was ending differently. The young man--his face was startlingly familiar, somehow--was not killing the old man. Those years of practice with the stun-pistol.... He stooped and picked the automatic up. The young man was unconscious, and The Guide had his pistol, now. He slipped the automatic into his pocket and straightened beside his inert would-be slayer. A shimmering globe of blue mist appeared around them, brightened to a dazzle, and dimmed again to a colored mist before it vanished, and when it cleared away, he was standing beside the man in uniform, in the sandy bed of a dry stream at the mouth of a little ravine, and directly in front of him, looming above him, was a thing that had not been seen in the world for close to half a century--a big, hot-smelling tank with a red star on its turret. He might have screamed--the din of its treads and engines deafened him--and, in panic, he turned and ran, his old legs racing, his old heart pumping madly. The noise of the tank increased as machine guns joined the uproar. He felt the first bullet strike him, just above the hips--no pain; just a tremendous impact. He might have felt the second bullet, too, as the ground tilted and rushed up at his face. Then he was diving into a tunnel of blackness that had no end.... * * * * *