The story, set in a world where humanity lives underground and relies on a giant machine to provide their needs, predicted technologies such as instant messaging and the Internet. The story describes a world in which most of the human population has lost the ability to live on the surface of the Earth. Each individual now lives in isolation below ground in a standard room, with all bodily and spiritual needs met by the omnipotent, global Machine. Travel is permitted, but is unpopular and rarely necessary. Communication is made via a kind of instant messaging/video conferencing machine with which people conduct their only activity: the sharing of ideas and what passes for knowledge.
The two main characters, Vashti and her son Kuno, live on opposite sides of the world. Vashti is content with her life, which, like most inhabitants of the world, she spends producing and endlessly discussing secondhand 'ideas'. Kuno, however, is a sensualist and a rebel. He persuades a reluctant Vashti to endure the journey (and the resultant unwelcome personal interaction) to his room. There, he tells her of his disenchantment with the sanitised, mechanical world. He confides to her that he has visited the surface of the Earth without permission, and that he saw other humans living outside the world of the Machine.
However, the Machine recaptured him, and he has been threatened with 'Homelessness', that is, expulsion from the underground environment and presumed death. Vashti, however, dismisses her son's concerns as dangerous madness and returns to her part of the world. As time passes, and Vashti continues the routine of her daily life, there are two important developments. First, the life support apparatus required to visit the outer world is abolished.