A young family move into a new apartment on the edge of town and hire a nanny to look after their newborn daughter. After gaining the trust of the young parents, the nanny begins scaring their young daughter and older son, Egor, at night. Egor tells his parents about their nanny’s strange exploits but they don’t believe him. For peace of mind his father installs security cameras, but they don’t register anything out of the ordinary. One day Egor comes home to find that his little sister has disappeared along with the nanny. His parents are in a strange trance-like state and don’t remember ever having a daughter. All her toys and clothes have vanished along with her, as if she was never there. Egor sets out with his friends to look for her. They are convinced that the nanny is actually an ancient Slavic demon that once went by the name Yaga. And if the kids don’t succeed in their quest, their parents will forget them too.