In a dangerously-close orbit around its star floats the Ancillary, a hollowed-out asteroid that harvests energy from the solar ring before relaying it deeper into the Sarian system. It fulfills the entirety of the Melisao Empire's energy needs--a masterful feat of engineering, once. Now, with the star it orbits dying and the departure of the Exodus Fleet near, the Ancillary's usefulness has come to an end. And so labors Javin, an aging engineer who must dismantle the structure he's spent his entire life maintaining. But there are those who would take advantage of the Empire's absence. Do they simply want the Ancillary and its precious solar panels, or are their motives more dire?