Ok so I was just hoping someone could help me find this story that I read years ago. It starts off with Draco saving Hermione from a ceiling collapsing on her or something and then the Slytherins have to move out of the dungeon because it's falling apart and the older ones move into the Gryffindor dorms. Hermione owes Draco for saving her life so they all team up to try and stop the dungeons from falling down and they have to make a potion or something. I remember that Blaise is in it and Draco and him get into a duel. Something happens to Hermione later on that only happens to muggleborns I think. I've tried searching for it but it doesn't show up and its really bugging me because the title is right on the tip of my tongue.