I've been looking for this fic and I can't find it, I lost it when my hard drive said good by to this world ='(

All I remember is that John sended Sam to investigate a case at a highschool and he pretended to be an student. I think Dean was a teacher? maybe even the principal. They get along, then start some sort of a relationship that was ment to end when Sam close the case and hit the road again.