In the farthest reaches of the Milky Way, the fates of a government agent, Aster, and a stoic ex-military man, Halan, become entangled after they find themselves trapped together inside one of many beacons that serve as a lighthouse for intergalactic travelers.

Every beacon is run by one highly trained human and a specialized Artificial Intelligence. When Aster mysteriously finds her way to the lonely beacon-keeper Halan, a tense battle of wills begins. Halan questions whether Aster is friend or foe, as her ability to disguise her agenda and motives could make her a formidable opponent.

Based on the best-selling book by Hugh Howey.