The events of the book take place in the 25th century. On the planet Earth, there have long been no countries separating people. Everyone lives in a single society—one where love and friendship, kindness and mutual help are valued, and where there are no wars or hunger. The book describes robot tests on the Moon, humanity’s first contact with the civilizations of the Galactic Council, the fall of an asteroid that led to adventures and mortal danger for some of the book’s heroes. During the adventures on the Moon, a military base of a previous Earth civilization was discovered.