“When Marvin was ten years old, his father took him through the long, echoing corridors that led up through Administration and Power, until at last they came to the uppermost levels of all and were among the swiftly growing vegetation of the Farmlands.”

Clarke packs a lot of exposition into a single sentence, letting the reader know who the main characters are, providing a general idea of where they are (the story’s setting), and establishing that they are going somewhere (hinting at the story’s plot). By telling the reader that “Farmlands” are on an upper level, Clarke immediately establishes that the story involves futuristic technology, as real-world farmlands are not typically on the upper level of human-created structures.

“For the first time in his life, he was going Outside.”

This sentence establishes the main dramatic event of the story while further elaborating on the futuristic setting. Going outside (which is capitalized as if it were something unusually important) is something Marvin has never done before, so the reader can infer both that Marvin’s world is unlike the real one and that something important is going to happen once Marvin is no longer indoors.

“He had seen it in photographs, of course: he had watched it imaged on television screens a hundred times. But now it was lying all around him, burning beneath the fierce sun that crawled so slowly across the jet-black sky.”

That Marvin has seen the “Outside” only in pictures and on television further emphasizes how unknown it is, creating suspense regarding what Marvin will find. The passage also uses lyrical language to describe the environment, with personified reference to the “fierce sun” and its animal-like movement across the sky.