A young family hires a nanny to look after their children, but after gaining the trust of the unsuspecting parents, their new guardian begins exhibiting some alarmingly unnatural behavior. When his parents don't believe his claims, son Egor is left to contend with the problem on his own, until one day he discovers that the nanny and his young sister have disappeared without a trace. With his parents now in a trance-like state, with no recollection of ever having had a daughter, Egor becomes convinced that his family has crossed paths with the ancient demon Baba Yaga. Enlisting his friends to save his sister, he must stop the dreaded Baba Yaga, before his parents forget him too!