Navasio tells the story of a race of beings left as guardians of a planet for 10,000 years. After a period of non-vigilance, a crescent appears in the night sky, a harbinger of doom for them, as the invaders desire to claim the resources the beings have taken for granted for so many years. The elders knew this day would come, and instructed the young that a steel bird (Navasio) existed, just for this purpose, and was prepared to take them  into space, where a series of 23 satellites would guide them to safety upon a distant moon. While in flight, the beings become aware of the fact that there is no satellite 23, and they set down on the nearest moon they believe can sustain their lives. Navasio crashes upon this moon, and the being are trapped inside of it, with no hope for escape. Only now do the beings start to understand what is it they had on their home planet, and what they have lost.