Oh, this is good. So, so good. Satisfying.
It's intriguing watching the plot unfold, and I really like the way it's written, the tone of it.
I was shocked by the young Severus - the way he seemed so different from the later Severus. More... sly and bitter, and less harsh and sour than the later Severus. It was fascinating to see that difference, and very convincing.
I would have loved more sex - but that's because the sex was good, and it's my greed speaking, rather than a criticism.