The plot covers a story of a group of astronauts who are approaching Earth after a 200-year-long journey on a long-distance spaceship called "Helios".

After landing they get isolated, and they quickly find out that the colony is ruled by an authoritarian regime, which tends to control all the people living there by means of censorship from one hand, and denunciation from the other one.

Also, to make the colony's population stable, there is strict birth control there, and people over the age of 60 get "retired", which in fact means senicide.

The colony's officials give vague explanations to the reason on why "Helios" has been diverted to land on the Moon instead of on its original destination, Earth.

The centre of the city is in turn inhabited by aggressive youngsters, their main occupation being apparently struggling between themselves and hunting for the individuals of the aforementioned suburban mob, in order to just kill them.

Initially, the aim of the protagonist is to collect information about the Earth's situation, share it with the rest of the "Helios"' crew who are remaining on the Moon, and arrange an escape also for them.