Before the heart surgery, the foster mother confessed to her daughter that she was not related to her by blood. The girl was found in the toilet at the train station with her younger sister in her arms. But the adoptive parents could not adopt both sisters. And years later, the older one wants to get to know the younger one's sister. Will the sisters find each other after almost 40 years?

After her mother's death, Natalia found a letter from her in which she admits that she adopted her.  And Oksana found out that she was adopted from her grandmother: the woman confessed to her in secret from her foster parents. Both heroines know the surname of their biological mother. But are they really siblings from the same family?