The Fortress – the only haven for humanity is falling apart. The destructive storms that have been roaring across the surface of the planet for centuries have caused irreparable damage to the ancient structure. Now the population of the Fortress is living in misery and deprivation. With the ever-present danger of overpopulation and with the occurrence of an epidemic a few centuries ago, a special law was introduced for all the 17 year-old boys. Since then, every year at the beginning of the Feeding Season, the Descent happens, which main goal is to decrease the general population of the Fortress. Now it’s Bars Ibis turn. He has only 24 hours to construct his Shell out of garbage metal leftovers, leave the safety of his only home and roam about the dangerous surface of the Earth. He and his coevals have only one mission – to survive the Feeding Season. If they live long enough, they have a chance of returning to the Fortress as Heroes, but their way back to is fraught with unexpected challenges and trials that aren't even mentioned in the ancient books. Will Bars find his way back to the Fortress and what bigger secret is he to find apart from the one that his mate, Thirteen, is so carefully hiding?