There once was a perfectly ordinary girl, Katya. And then—bam!—there appeared another Katerina, an exact copy of Katya, if you don’t count her disgusting behavior and that small detail: Katerina is, in general… a witch.
Now Katya faces a difficult task: to reform a young witch. And until that happens, her own thoughts and feelings will have to make some room, because Katerina’s consciousness will live in her head.