My Heart with You (2018)

A modest math teacher Olga (Olga Pavlovets) devotes herself to her family-her husband Vadim (Ilya Obolonkov) and daughter Lena. Vadim, behind her back, lives for his own pleasure, turns novels and at one point completely leaves the family for his mistress. Olga is left alone with a small daughter without means of support. She is forced to file for child support, but her husband discovers a startling circumstance: It turns out that Lenochka is not his daughter. Olga is crushed by such undeserved slander, because she knows that she was faithful to her husband. But the most terrible test awaits her ahead, when Lena falls seriously ill. Olga is ready to become a donor, but the hospital tells her that all these years she raised someone else's child - Now Olga will have to understand how this could happen, find the real parents of Lena and save the girl from death.