Earth, which is dangerously radioactive in many spots, still is recognized as the birthplace of humanity, and to its university, the University of Earth, come students from many other planets. One of them is Biron Farrill, son of the ruler called the Rancher of Widemos, of the agricultural planet Nephelos. Biron is within a few days of graduation when he is awakened in the night by a visiphone call from a fellow student, Sandor Jonti. But the sending part of the visiphone does not work. Neither do the lights, ventilation, or door when Biron tries to escape a "radiation bomb" building toward explosion in his closet. Jonti, however, blasts the lock, releases Biron, and tells him his life is in danger; his father has been arrested by the Tyranni and may have been executed. Biron, under an alias, should go to the planet of Rhodia and the court of the Director of Rhodia, Hinrik, who has influence with the Tyranni and may be able to get Biron reinstated as his father's successor. Biron
reflects that he has not found the Earth document his father had asked him to locate but decides to leave as Jonti suggests. In a personal-beam transmission from the planet Lingane, Jonti learns that the Rancher of Widemos has indeed been executed. Jonti says that Biron is expendable. A bit later he learns from Rizzett, his agent, that the document both he and Biron had been seeking has been missing for twenty years.