Lyssa Arthurs seemed to muse for a moment. "Yes," she said. "I see.... Whoever built the fortress must have built this miniature cavern before they reduced their size, since this building is constructed all in one piece, and not of blocks cemented together. And you wouldn't expect little people to do that very readily. Then they came down through the vat apparatus. But why, Perry? Why did they want to be small? What advantage was there in it? Who were they?" * * * * * Overhead, in the arching dome, Perry Wilcox noticed a picture. An ocean washing a jagged shore. It looked just like a modern ocean. Only, in the gorges between the jagged volcanic bluffs, there were bizarre, fernlike trees, such as had existed in the Terrestrial Carboniferous Period. "I think," he said, "these people came from another planet. That ship looks like a space ship." "Do you really think so?" "Yes, and it was a tough world for a raw bunch of colonists," Perry went on. "So it was probably easier for them to make a small world of their own. One they thought they could regulate and control. Only--there was something wrong with it. That's why they're extinct." "I guess you're right, Perry," the girl offered. "They built the fortress. It was their first encampment, within which they could make their preparations. Then, when they were ready to become small, they covered it over to hide it. The automatons were sealed up, with special apparatus to make them active--if there was danger--if some snooper came around. For instance you, Perry. Our being sent down here, was part of the plan too--captives or guests. Only the little people who were supposed to receive us, have disappeared." It was obviously true. The valley of the cavern looked deserted to its farthest, verdure-clad reaches. The buildings, peeping white through the green, were skeletally silent. There was no sound. The desolation got on Perry Wilcox's nerves. The vast futility of the mechanical debacle going on above. A dream that had soured. A science of miracles that had followed a Will-o'-the-Wisp to a dead end. And then Perry thought of something that changed his mood. "They must have had a way to control the robots from here, Troubles," he said. "Everything else is too perfectly arranged for it to be otherwise. They wouldn't just lock themselves down here, blind to the upper world, would they? There must be a control room somewhere. And logically it should be in this building, since it's the most important-appearing one in the place." CHAPTER V Nemesis from the Tiny Perry and Lyssa found what they were searching for at last, after climbing a long, spiral stairs. The chamber was round, and was above the dome of the temple, just beneath the representation of the space ship and the golden statue of that ancient leader. The disk-shaped door was fastened by a great hasp that was disengaged easily.