Mere, a wraith made of a supposedly-soulless collage of android and flesh, only has one job—to execute the wolflords, outcasts of the Principality. The Principality is the expanse of space co-ruled by the Sun Lords, cosmic beings who'd warred with one another for centuries. This collective empire is their attempt at peace. Anyone who defected is subject to their wrath. Once, a slave escaped their rule to Planet Olinara V, and the Principality destroyed the entire planet as punishment.

Mere is a mere instrument of the Sun Lords' punitive rule. It has no memories of its past and doesn't care to wonder about its creator. However, it does wonder about political poetry; the taste of stardust wines; and other luxuries for the living. Mere hides its desire to live though, because it also knows fear, and to stray from its role is certain death.

However, when Mere is assigned to kill the last of the wolflords, all of the order Mere has operated by unravels. This wolflord knows and claims on his dying breath to have loved Mere, and though Mere doesn't recognize its last victim, it is consumed with what feels like grief. The wraith executes the wolflord, but not before secretly stowing away his final memories, which Mere tries to make sense of in its pod later on.

Soon after the execution, a strange woman appears in Mere's chamber. Her name, she reveals, is Century, and she is there to free her creation: Mere. They escape, though not without the Principality raising the alarms. As creator and creation speed through space, Mere discovers it was made from the pieces of Century's enemies as the ultimate act of vengeance. The last wolflord, Kitshan Zu, was its lover and Century's servant. Century had liberated Mere in honor of Kitshan.

Mere's liberation, though, isn't its first priority. The wraith wants to make amends to the people it has executed by rescuing their soul pebbles and taking them to the mythic planet, Rebirth, where life is rumored to bloom anew. After much convincing, Century agrees, and the two detour to the Red Sun Lord, champion of death. They convince the Red Sun Lord to come with them to the Courts of Tranquility, where the soul pebbles are stowed, and the God's presence is enough to distract the courts. Mere steals the pebbles and races back to the ship, where it gets caught in an attack by security guards. Century reveals herself to be a Sun God herself and saves Mere.

The two travel to Rebirth and release the pebbles into the earth, where they begin the renewal process. Century and Mere come to peace with one another, and Century chooses to stay on Rebirth and rest. Mere leaves its creator, but just as it is to enter the ship, it is greeted by the Principality's butcher-drones. The wraith knows that if it tries to hide, the butcher-drones will decimate Rebirth, just like they destroyed Olinara V. Mere, caught between the intense and all-consuming desire to live and the debt it owes to those it has executed, chooses to sacrifice itself in order to save the planet that inhabits the souls it has killed. Mere composes one final poem, dedicated to Kitshan, before it is killed.