I like....hardly even know what to say. This is not at all what I was expecting but it was so much BETTER and I just...yeah. Okay. Will try to be coherent.
I LOVE that you set it at Durmstrang. Durmstrang is so FASCINATING and we know so little about it and I love that you pulled that aspect into the plot too, that the whole reason Harry went in the first place was to find out more about Durmstrang. And the magical THEORY - the way they use Dark Arts but not on humans, the fact that they're so advanced with it, that they use it for HEALING and to make them better AURORS and gah...and the way you pulled in the theory, the brief and offhanded-but-intelligently-so mentions of these different types of magic...there's nothing I love more than that kind of grounding, the way it feels like this is all established theory by the way it's mentioned, but that it's actually introducing new material. I love the DETAIL of it too, the sunrise mirage, the bath ritual, the translation potion, the Quidditch and how it's different from Hogwarts'....
DRACO TOLD HIM HE'D PUT THE LOVE POTION IN. Oh god. That KILLS me. I was wondering about that from the start, why he would joke about something like that, and then forgot about it, and then you brought it back and GOD *___* I was also wondering about why Draco was so personable since the last we knew was that he hated Harry, and I wondered why Harry was all 'mmm, time to shag Draco', and it seemed a little abrupt to me, but it didn't seem abrupt to Harry which was even more confusing, and then it all made SENSE and I actually laughed out loud in glee. I love the idea of Draco being brilliant enough to make this awesome love potion, and that he hints at it not just by telling Harry he's been potion'd, but also with the mentions of enjoying potions so much.
I love the way Draco talks about being saved by Harry. I love that he's a good teacher! I've seen so many stories where he becomes the next Snape, only people don't notice because he's so pretty that all his students want to shag him, but in this, it's clear that he's really GOOD, and that appeals to the dorky I-love-teaching side of me SO much. The other thing that had me shrieking was the mention of a priori - it was briefly, and totally in passing, but I actually squeaked a little bit.