Finally, the heroes familiar to us from previous books are in space, at real work! The Gagarin orbital station, the lunar city of Lovell and another station hanging on the opposite side of the earth’s orbit, three hundred million kilometers from Houses. And also - events, all the more unexpected because they came from where, it would seem, nothing could come in principle - from the mysterious alien artifact “star hoop”. And it’s not to say that these events were so harmless - just as the plans that the young, ambitious astrophysicist Lednev, working at the Lagrange station, are making are not harmless. Of course, a risk is a risk - but humanity has come out - really come out! - into space and is now uncontrollably rushing forward, to the stars, and each of our heroes is doing everything in his power for this...