I was thinking of maybe doing a HarryxOC pairing and the plot would be that my character discovered her powers at 11 years old and when her parents found out they disowned her. So she went from foster home to foster home for 5 years until she ended up running away and living on the street. Well, now she's been living on the street for 2 years and now she's 18 and people look at her like she's a freak because she lives in a small town so everyone knows about her.
I was thinking that maybe she lives in Harry's old neighborhood and now he's a professor at Hogwarts. Maybe it goes back just to see if anythings changed and he stumbles upon her and sees that she is a witch and offers to help her.