The novel concerns a generation ship built in the style of a Stanford torus traveling to Tau Ceti in order to begin a human colony.

After having some trouble with understanding the human concept of narrative, Ship eventually elects to follow the life of Devi's daughter Freya as a protagonist.

The ship itself, which has been moving towards self-awareness, takes physical control of the situation by lowering oxygen levels and separating warring factions, referring to itself as "the rule of law".

It then reveals to the crew that there were in fact two ships originally launched for the Tau Ceti expedition, but the other was destroyed during a period of severe civil unrest, and the collective memory of that event was erased from the history records.

Unable to reach consensus, the factions agree to part ways, with those who wish to stay retaining as many resources as can be spared to pursue an unlikely attempt at terraforming the Mars-like moon Iris, while the other group, led by Freya, opt to try and return to Earth.

Ship manages to safely drop its humans off on a pass of Earth but fails to make a final gravity slowdown past the Sun.

Major themes in Aurora include complexities of life aboard a multi-generational starship, interpersonal psychology, artificial intelligence, human migration, environmentalism, and the feasibility of star travel.

[6] Stephen Baxter, James Benford and Joseph Miller wrote a detailed critique of the novel's science for the website Centauri Dreams, concluding that "while Aurora is an intriguing combination of literary, political, scientific and technical notions, and while it reflects many current speculations about the difficulty of interstellar travel, in many instances it lacks the supporting credible scientific and technical detail required to make its polemic case that human interstellar travel is impossible."