The miniseries follows the lives of Tatiana, her two daughters and her granddaughter. Tatiana is a fitness instructor at one of the best gyms in town, her elder daughter works as a secretary in a company while the younger still goes to high school. Tatiana’s experiences with men and in marriage have been painful. She tries to inculcate that same mistrust to her daughters… But it all changes when one of them falls in love!

Maksim, a young and promising ethnographer and postgraduate student, arrives in the village of Rusalino to collect old folklore songs, tales and traditions for his papers in 1993. It was Liuba, a student of the same college, who persuaded him to come to this village, because her aunt, Varvara, lives in Rusalino and the area is famous for having preserved many old songs and rites. The girl believes sincerely that their scientific journey will help them get closer, because she is incredibly in love with Maxim. Liuba does not even suspect that here, in Rusalino, Maksim will meet Rada, a Gypsy girl, who will steal his heart for the rest of his life.

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.

"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.