After a time the few people--some few thousands--who knew that there was a space-liner named _Icarus_, gave it up for lost. They forgot about it. Everybody forgot. Even the passengers and crew of the ship forgot it. Not immediately, of course. For the first few generations their descendants cherished hopes of rescue. But the planet which had no name--the forgotten planet--did not encourage the cherishing of hope. After forty-odd generations, nobody remembered the _Icarus_ anywhere. The wreckage of the lifeboats was long since hidden under the seething, furiously striving fungi of the soil. The human beings had forgotten not only their ancestors' ship, but very nearly everything their ancestors had brought to this world: the use of metals, the existence of fire, and even the fact that there was such a thing as sunshine. They lived in the lowlands, deep under the cloud-bank, amid surroundings which were riotous, swarming, frenzied horror. They had become savages. They were less than savages, because they had forgotten their destiny as men. _1. MAD PLANET_ In all his lifetime of perhaps twenty years, it had never occurred to Burl to wonder what his grandfather had thought about his surroundings. The grandfather had come to an untimely end in a fashion which Burl remembered as a succession of screams coming more and more faintly to his ears, while he was being carried away at the topmost speed of which his mother was capable. Burl had rarely or never thought of his grandfather since. Surely he had never wondered what his great-grandfather had thought, and most surely of all he never speculated upon what his many-times-removed great-grandfather had thought when his lifeboat landed from the _Icarus_. Burl had never heard of the _Icarus_. He had done very little thinking of any sort. When he did think, it was mostly agonized effort to contrive a way to escape some immediate and paralyzing danger. When horror did not press upon him, it was better not to think, because there wasn't much but horror to think about. At the moment, he was treading cautiously over a brownish carpet of fungus, creeping furtively toward the stream which he knew only by the generic name of "water." It was the only water he knew. Towering far above his head, three man-heights high, great toadstools hid the gray sky from his sight. Clinging to the yard-thick stalks of the toadstools were still other fungi, parasites upon the growths that once had been parasites themselves.