Adopted By Andy Hurley: A Fall Out Boy/Panic! At the Disco/other band fanfic

Caitlyn Alexandra Moore was a shy and reserved girl, always getting good grades and not getting in trouble at all.
Until she was ten, that is. You see, when Caitlyn was ten, she had come home from school one day to see a mysteriously familiar man stab her mother and father to death in front of her. Their last words were how much they loved her and how proud of her that they were.
She was put into an orphanage, but the older girls made fun of her and beat her sometimes to get her to say something. She had terrible anxiety and became clinically depressed, and by the time she was 15, it didn't show. She knew how to cut the emotions off, and that was one of her respected traits.
One day, when Andy comes to adopt a child, he sees Caitlyn all alone. He talks to her, and she looks up and gasps. She recognized him from somewhere.
Will this story have a happy ending or will Caitlyn and Andy not get along very well? Will they have to go rescue the girl they call their own?
Read and find out....