A new Soviet life is emerging in a new Moscow microdistrict. New people, new families, new neighbors. The elevator is not yet working, or is no longer working due to constant overload due to transporting furniture. Neighbors are just getting to know each other, getting to know each other, and gradually the lives of different families imperceptibly begin to intersect.
A mysterious castle has stood on the island for 300 years, about which there are many legends and rumors. In reality, the castle is home to a boarding school, but local residents are sure that the ghost of the Green Hunter lives there. The boys also think they hear footsteps at night. And they were not mistaken - their search for adventure leads them to the sinister secrets of people who collaborated with the Nazis during the war.
On the example of the history of the discovery of the "solar substance" Helium, the history of the most important discoveries in the field of physics and chemistry of the early XX century is given.