Wow. Utterly fascinating. Suspense, mystery, drama, romance Snarry-style - your fic has them all. I loved the slow unravelling of the mystery, and your ingenious explanation caught me completely by surprise in spite of various little hints along the way. I loved the gradual development of Harry and Snape's relationship with all its pitfalls but ultimately happy resolution - and, of course, the amazingly hot sex!
This is one I will definitely come back to and read again when I have more time to savour every detail.