In a group of more than two persons there's always one who feels a little bit more outside than the others... Have you ever considered that maybe it's the same with One Direction? Maybe all of them isn't as happy as it looks like. Maybe one of them feels a bit outside. Maybe one them feels lonely?
An ordinary teenage girl comes really close to one of them and realize that it isn't what it looks like. She realize that everything isn't perfect and that even with millions of teenage girls dying to meet you, you can still feel lonely.