The alien Luri, almost a teenager, fell to Earth on a special mission. The neighbors in the Galaxy were terribly offended by earthlings for their attitude towards their planet and Luri was sent to us in order to inform us that in a few hours time on Earth would turn back - a century ago, and all this so that people could re-live the 20th century "ecologically right and safe." However, for the heroes of the film, this can simply mean death, because there will be no place for the living in the world of great-grandparents and great-grandparents.  Luri's meeting with peers, the girl Masha and her friends from around the world can interfere with what was planned and save all those living today.