This was absolutely delightful. Plotty, witty, and full of really words (I'm a bit of a word-freak). I couldn't have asked for a better gift. This is, too, quite possibly one of the best fics I've read in a very long time. Thank you, mystery author, for such incredible attention to detail, nuance and gifted storytelling.
A few of my favorite things:
The naturalness of the dialogue, including the intricate affectations of speech and manner.
The characterization of Harry and Snape--perfect without being overdone. Really lovely.