I had no time to comment when I first read this fic, but I made a mental note to come back because it was so strikingly good. So I've read it again, and it's just as wonderful the second time around. The dark, desperate poetry of the Occlumency sections, the imagery of pebbles sliding through Snape's fingers, of Snape's invading magic like vines in Harry's head, the punishing repetition of Legilimens and Harry falling and sweating and bruised and struggling to his feet to try again - it's so beautifully written, both hallucinatory and extremely physical, and there's an exhausted, erotic tension running through it that's positively squirmy because it remains unacknowledged.
Then the scenes in St. Mungo's are claustrophobic in a different sense, and the way Snape and Harry communicate, almost in code, proceeding by verbal fencing matches - which Harry keeps losing, getting lost in, just as he lost at Occlumency, until the tables turned and he won - it happens here, too. Poor lovelorn Harry. Snape is the most unforthcoming character imaginable, and he distracts and denies Harry until - until he can't anymore. And his concession, small as it is, is, to use his own words, of "epic magnitude." I love that entire last exchange, the ricochet between them that stops with, "You like teaching me." It brings a perfect burst of momentum, of desperate bargaining, to the narrative - a smackdown of clarity - just before the quiet accord at the end.
To repeat, the writing in this piece is exquisite, with an eye for physical detail and an emotional control that's both oblique and very powerful. Which makes me suspect I know who you are. It reminds me for some reason of music, of musical form and dynamics. I don't expect that to make sense. :) It's just a way of saying that this fic has its own tempo and its own internal harmony, its crescendos and variations, entertaining us with the beauty of its surface. But beneath that surface lurk more eloquence and unspoken emotion than the words can hold.
Or in the short version: my hat's off to you, mystery author. Thank you for a complex and almost spellbinding fic.