Twelve-year-old Rosie Oakes suffers from a lack of maternal love all her life, until one day she finds the book "Guide to the Universe of the Witch Hunter." This is how she realizes that her mother is the last witch hunter, nightmarish and invincible creatures. But many years ago, one of the witches, a Memory Thief, put a curse on her so that she would forget about the most precious thing — love for her own daughter. Now Rosie must defeat the witch and save her mother, but for this she needs not only to find a weapon against witches, but also to reveal the secret of her birth.