The novel's title itself refers to a quest undertaken by most of the inhabitants of Carter-Zimmerman ("C-Z"), a polis devoted to physics and understanding the cosmos, along with volunteers from throughout the Coalition of Polises. The Diaspora consists of a collection of one thousand clones (physical copies of the polis hardware) of C-Z polis, deployed toward stars in all directions in the hope of gathering as much data as possible in order to revise the long-held classical understanding of Kozuch Theory, which had failed to predict the Lacerta event. The bulk of the novel follows this expedition, rotating back and forth between different cloned instances of the same cast of main characters as different C-Z clones make discoveries along the way, relaying information to one another over hundreds of light years—and finally between several universes.