An anonymous inventor sends copies of the "Gismo" through the mail to hundreds of people. Civil society immediately collapses; as one news commentator says: "The big question today is: Have you got a Gismo? And believe me, nothing else matters." The story jumps to the year 2149: the society we know has been replaced by a society of wealthy minority supported by slavery, and access to Gismos is jealously guarded by Gismo-produced slave guards. The story is told through the eyes of Dick Jones, the son of the leader of Buckhill, a compound in the Poconos. Jones is coming of age and is about to be sent to Eagles, another, larger compound in the Rocky Mountains, for military training. Jones is initially presented as an unsympathetic character: spoiled, impulsive, hot-headed. In his final day at Buckhill, he insults a cousin who then challenges Dick to a duel; Dick kills him, and has to be ushered away in secret the following morning for fear of retribution.

Jones arrives at Eagles, a fabulous city built into a mountain. Like Buckhill, Eagles is run as a slave society; but Jones is startled to realize that the Gismo is used to duplicate slaves, and that the most trusted slaves have been copied hundreds of times. Status among citizens is determined by social connections, and, for males, by skill at hand-to-hand combat. The author shows us the dark side of Eagles; for instance, the Boss takes pleasure in having slaves dropped down a shaft inside a tall tower and watching them plunge to their death via closed-circuit television. This may be done because it is suggested that all but the very best of slaves are "recycled" at about 30 years of age but with a 300 slaves for every freeman ratio at Eagles, some slaves live much longer.

There are hints from Jones's father in Buckhill that the slaves are contemplating revolt. In Eagles, Jones is introduced to a secret society that debates the merits of the slave culture and that plans a revolution, with the collaboration of a disaffected member of the ruling family. Jones is enthralled by the arguments he hears. At these meetings, the reader discovers that once the Gismo was sent out and the initial battles were fought, almost no scientific advances were made because the Gismo could do everything. It is hinted that some saw the time of chaos as a chance to advance space exploration but some people from the meetings say that it was all theory and nothing was ever built. But before the revolution can be put into action, the slaves revolt, killing most of the free citizens in Eagles and Buckhill, including Jones's family. Jones is forced to choose between his allegiance to kin and his yearning for a better society. In the end, Jones chooses to turn against the slaves so that he can become "The Man" at Buckhill replacing his murdered Father and getting society back to where it was when he left for Eagles.

• A for Anything title listing at the Internet Speculative Fiction Database