Love is not an exact science at all, and even a first—class math teacher sometimes cannot figure it out. Maria Pavlovna is forced to seek help from a colleague who recently came to her for advice. Meanwhile, the rest of the teachers are again suffering from Natalia's management methods. This time, the head teacher violated the sacred tradition of the school.

On the eve of Mother's Day, the women of the Trifonov family have everything awry. The head teacher is on the verge of dismissal due to the sad situation with the director. Maria Pavlovna and Nastya quarrel: they will not decide in any way whether it is worth intervening and defending Natalia's honor. Strangely enough, they will be helped by colleagues who have become very attached to all three of them.