The young family moves to a new apartment on the outskirts of the city and hires a nanny for their newly born daughter. Having come to trust, the nanny at night scares the infant and the eldest son Egor, who is trying to tell the parents about the strange behavior of the nanny, but they don’t believe him. To calm the father installs surveillance cameras, but everything turns out to be in order, nothing suspicious has been found. When once Egor returns home, he does not find a nanny or a little sister. But parents are in a strange trance and do not remember that they had a daughter. Surprisingly, with her baby all her toys and things disappeared, as if she had never been here before. Egor and his friends go in search, confident that the nanny is in fact an ancient evil demon, popularly called Yaga. And if they do not cope, their parents will also forget them.