I have spent the past two days going back and forward reading this piece of pure art. I loved it in a sore and wonderful way.... ah... caught myself reading out the words aloud (and I have a 4-year-old, you gotta be careful, but it's SO well written).
Your style is artistic and it's more than a good fanfic, I hope you are earning money with writing and aren't a cleaner or something :P
I loved Nightwatch, too (Angus McSomething-Something was something I had to laugh at several times a day, even in the bus) but this one is... so good, so good.
Sev's breakdown at the beginning made me weep and his aunt made me laugh (I actually KNOW people like that). The smut was brilliant and sweet and very well written.
There is a tiny mistake in: (March. Severus is 28, Harry is 23.) a few lines later you say he is 27 when he is 28, just saying...
Otherwise it is perfect. I loved how well thought through it was, perhaps a little like the math formula of a prodigy.
I am enthralled and I love your writing, love it, love it, LOVE IT.
I only registered in IJ for being able to write a review.