"Your husband is sleeping with your student" – Olga finds such a note in one of the bouquets that were presented to her in honor of her triumphant speech at the scientific forum. Olga is a mathematician. She can easily figure out who sent this anonymous letter. Except this man is found dead. This is how a dangerous game begins, each move of which is associated with one of the Fibonacci numbers. What do they mean and how are they related to Olga's life? The answer is far in the past. Every mistake will cost the life of someone close to the heroine.

During the celebration of the dean's anniversary, mathematician Olga Barkovskaya finds the culprit of the celebration murdered. Next to the body is a card from an unknown game, very similar to the one that was thrown to Olga the day before. It seems that Barkovskaya is being invited again to solve a mathematical puzzle, and a human life is at stake.

August 1980. The Soviet authorities are preparing Moscow for the Olympic Games and expelling unreliable citizens from the city. One such citizen is the talented cellist Arseny Chaika, who ends up in the village of Protasovo with his rabbit. Meanwhile, in Moscow, foreign journalist William Smith is looking for him for an interview.

The beginning of the 2000s. New realities, instant adaptation to the proposed circumstances, enchanting careers, unexpected unknown professions... All this could have happened only at the turn of the century, when the Soviet system instantly went out of fashion, replaced by the lightning invasion of the Western world in a grotesque parody. The main character of the film is an inconspicuous girl Nadezhda Strakhova. Nadezhda, oddly enough, is married. Her husband, Vitalik, a provincial, married a childless Nadezhda for the sake of a Moscow residence permit and a typical "Khrushchev" on the outskirts of Moscow. Nadezhda works two jobs to support her small family: in the mornings in the district library and in the evenings in the theater wardrobe. One day her life changes dramatically.