Five hundred years have passed since the end of the Second Great Assa. Destroyed cities and estates have long been rebuilt, the damaged planets have been cleared of toxic substances, scorched forests have been raised to the very skies, and those who fell in battles have long been avenged. The warrior race has no more serious matters inside the Frontier, but the cover squadron of the Yarilo star system has enough trouble every day . The squadron is forced, in peacetime conditions, to keep in the strictest confidence the existence of an entire solar system, populated by a billion cheerful, inquisitive and overly active representatives of civilian castes. And then civilians are looking for ways to stay in the low-energy galaxy, refugees of low-energy races are coming from beyond the Border, in the neighboring galaxy, the weapon of the Dark Emissary burns out entire solar systems, and the Harmonious Beauty disappears during a routine flight to a neighboring system...