In the forty-first century, the human race has spread out to occupy part of one arm of the galaxy. Two problems vex the species at this point. First, the "K-field" technology that allows interstellar travel and provides unlimited energy is dangerous and difficult to handle. The problems with managing this technology tend to cause societies that use it to stagnate. Second, an artificial virus has been created that destroys the free will of humans, and has led to a resurgence of slavery.

The largest and strongest government is the "Chrysanthemum Throne" an empire that bans the virus and maintains order within its aegis. However, when the current emperor dies, he will be suceeded by his venial son and the empire will degenerate. The Chrysantemum Throne is descended from a coalition of Japanese and international corporations. Previous dynasties were ethnically Japanese, but the current ruling family is American.

The emperor's daughter, Fujiama, a PhD in history, believes that, contrary to the popular narrative, the original home of humanity still exists, isolated in the far reaches of inhabited space, and will have valuable information on how to manage the human race. The emperor summons his best admiral, Ethan Kharg, and directs him to take the princess to find Earth and establish relations.

The expidition journeys outward in the admiral's flagship, the battleship William Lloyd Garrison, followed, inexplicably, by a spacecraft belonging to the only intelligent alien species known. This vessel possess a technology that makes it difficult to track.

Fujiama is attracted to Jason, a naval officer in charge of "External Affairs." She becomes friends with the onboard marine contingent and has conflicts with the ship's captain, the ferocious Mary Ashid. She also meets the admiral's aide, Elaine, who is rumored to be his lover and whose behaviour raises questions about the legitimacy of the relationship. It will take months, possibly even a year to reach Fuji's putative location for Earth, and it means a voyage through progressively less known and increasingly hostile areas.