A world in which, as a result of an unknown cataclysm, humanity is forced to live under opaque domes that imitate the natural sky, covering individual villages and cities. For the first time in history, it is possible to go beyond the horizon (the border of the dome) in the literal sense of the word, but the problem is that such a daredevil will not be able to return back. It would seem that the problem is not so significant, because life under the Dome is quite prosperous and safe. Why, one wonders, look for adventures on your own? However, the main character of the novel, named Gars, is ready to do anything to find out what lies beyond the Horizon...