Odd-mannered, obsessive, withdrawn, Aster has little to offer folks in the way of rebuttal when they call her ogre and freak. She's used to the names; she only wishes there was more truth to them. If she were truly a monster, as they accuse, she'd be powerful enough to tear down the walls around her until nothing remained of her world, save for stories told around the cookfire.

Aster lives in the low-deck slums of the HSS Matilda, a space vessel organized much like the antebellum South. For generations, the Matilda has ferried the last of humanity to a mythical Promised Land. On its way, the ship's leaders have imposed harsh moral restrictions and deep indignities on dark-skinned sharecroppers like Aster, who they consider to be less than human.

When the autopsy of Matilda's sovereign reveals a surprising link between his death and her mother's suicide some quarter-century before, Aster retraces her mother's footsteps. Embroiled in a grudge with a brutal overseer and sowing the seeds of civil war, Aster learns there may be a way off the ship if she's willing to fight for it.