The first strike of a mysterious alien civilization almost destroyed the Earth. High civilization has been preserved only in space colonies; the surviving population of the Earth has been thrown back into post-apocalyptic barbarism. Centuries later, the memory of a distant enemy turns out to be weaker than hostility towards one’s neighbor. Captivated by political squabbles, the inhabitants of the Earth and its space colonies do not want to notice hidden signs of the return of aliens who are preparing to establish complete control over humanity. The heroes of the novel - the daughter of the commander of the Space Fleet, an ordinary teenager from a “barbarian” settlement on Earth and an operative of the special service of one of the colonies - experiencing various adventures, are moving towards realizing the shocking truth about the true place of humanity in the Universe.