The relationship between Katya and her mother cannot be called simple anyway, but here, in the midst of the working day, Katya learns that her mother never flew with her friend to the resort, disappearing from the airport in an unknown direction. Having learned from the doctor the real reason for her mother's strange behavior, Katya not only reunites with her, but also reveals a lot of new things about her mother and herself.
When the mother and father of ten-year-old Lena and Marusya decide to get married, these two completely alien girls are forced to become sisters. Now they share one room, one class, friends, and most importantly, they are fighting for the attention of their parents. Each of them dreams of returning to their former life, and for this it is necessary to embroil adults.