This story takes place 50 years after the events of "The Psychohistorians". Terminus faces the first of many "Seldon Crises". With no mineral wealth of their own, the people of the Foundation become cut off from the rest of the Empire, as a result of the breakdown of law and order in the outer regions of the Galaxy and their neighboring planets' declaration of independence.
Terminus is caught in a feud between four planetary systems which have degenerated to a barbaric state and find Terminus's location a strategic advantage. The Board of Trustees of the 'Encyclopedia Galactica Foundation', composed of scientists with no political or military training, find themselves incompetent to handle the situation as they are distracted by their work on the Encyclopedia. But the Mayor of Terminus City Salvor Hardin perceives the threat and quickly finds a solution; to play the four kingdoms off each other.
Hardin's plan is a success and then the image of Seldon appears in the "Time Vault", where he acknowledges that the "Seldon Crisis" was averted. Seldon makes it clear that the choice made was the intended one and that the Encyclopedia was just a distraction to further the overall plan.