An ambitious professor of psychiatry, Viktor Meshchersky, conducts a dangerous psychological experiment in which, under false pretenses, he locks victims and their abusers in the basement, hiding his true goals. The subsequent investigation will reveal the real motives of the professor, and will tie together the confusing stories of all participants in the cruel experiment.
Life on Earth has changed after the visit of alien ships hovering in various parts of the planet. Their passengers — biopages or "Vitaliki", as they are popularly called — produce a substance called "prak". Its purpose, as well as the purpose of the aliens' visit, is unknown, but nurse Nina (Irina Salikova) from a quiet provincial town hopes to help her sick father with the help of prak. After contacting Vitalik, Nina learns the truth about extraterrestrial beings, which completely changes her life.