A mysterious new witch professor arrives at Hogwarts mid-term, replacing a teacher no one will explain. She is strict, brilliant, and unnervingly calm, with a reputation for punishing rule-breakers and reading people far too easily. Students whisper that she came from a hidden branch of magical research, or that she once served a dark purpose and is trying to outrun her past.

The story begins when she first encounters a particular student who seems ordinary at first, but somehow reminds her of someone she lost long ago. She is harsh with the student in public, but quietly begins testing them in private, setting them impossible tasks and watching how they react under pressure. The student suspects she is hiding something dangerous, while she realizes the student may be tied to the secret she has spent years protecting

She makes you go to her office