The young family moves to a new apartment on the outskirts of the city and hires a nanny for their newly born daughter. Having gained trust, the nanny at night scares the baby and the eldest son Egor, who is trying to tell the parents about the nanny's strange behavior, but they don't believe him. To calm the father, he installs surveillance cameras, but everything is normal and nothing suspicious is found. As soon as Egor returns home, he can't find the nanny or the little sister. But the parents are in a strange trance and don't remember that they have a daughter. Surprisingly, she takes the child and all the toys and things are gone, as if she had never been here before. Egor and his friends go in search, convinced that the nanny is actually an ancient demon, popularly known as Yaga. If they can't cope, their parents will also forget about them.