This was really intriguing, and highly entertaining. I can easily see Snape getting along quite well all alone for some time, finally free of his burden of servitude. And then--ow, my heart--his Potions breakthrough and the awful realization that he can't share it or ever be recognized for it. Again.
Then Remus's appearance, and how Snape struggled to not show how glad he was of it, not even wanting to be glad of it. And Remus's joy at being free of his curse, loping around through the forest and just delighting in the full moon--very nice.
And then the setting up housekeeping and the research and the speculation, and, inevitably, the frottage in the forest and hand jobs in the hall gradually led to blow jobs in the basement--great line! and the evolving relationship eventually bordering on tender, but never sappy.