Sometimes there was a dry ledge upon which they could walk. Sometimes the river deepened, and they had to swim. Always Degg advanced grimly, steadily, and silently. A foreboding grew upon Martt. Were they going right? Was this the way Frannie and Leela had gone? Once he whispered, "Do you think, Zee, that he's tricking us?" She shook her head. "You have all the drugs. He would not dare." They had waded for hours. Then ahead of them they saw Degg pause. The river here plunged straight down into a black abyss. To the left a passageway turned upward. It was some ten feet high and two or three times as wide. It went up at an incline into the green, luminous darkness. They followed Degg. A mile perhaps, steadily climbing. Martt calculated. They had already walked possibly fifteen miles--and they were more than eight times the normal size of Zee's world. That was more than a hundred and twenty miles underground--most of it downward. Martt realized that he was tired. And hungry. Before leaving Reaf he had thought of food necessary for this trip. Degg had a concentrated food--a dull brown powder. Martt promptly had appropriated it--had tested it to make sure it was not a size-drug. . . . The passageway abruptly opened into black, empty space. A rocky slope rolling gently upward, strewn with huge black boulders. It extended as far as Martt could see, upward into a luminous darkness. Overhead was a black sky--murky with distance. Degg stopped. "We begin getting large here." Zee translated it to Martt. "Let's eat, then," said Martt. "Zee, aren't you tired and hungry?" There was water lying in flat pools on the rocks. It was clear, cold and sweet. They sat down, talking and eating. Then Zee slept. And Degg slept also. Martt sat alert, watching, while the headless thing stretched itself somnolent on a rock near by, its single eye on the stalk wilting downward in drowsiness. Martt strove to master his revulsion. He called softly, "Eeff! Eeff, come here!" But it would not come. It moved farther away, whimpering to itself. IV "Zee, wake up! We've got to get started. You've slept hours." The real size-change now began. In single file they walked up the black slope. It shrank beneath them--creeping, crawling, dwindling away under their feet. The boulders shrank into rocks, into pebbles. In an hour they were walking upon a smooth surface. The black void was no longer empty. Mountains showed ahead--and to the sides. Giant faces of rock, looming into unfathomable distance of the black sky. The mountains were drawing closer; contracting, rushing down with a violent movement.