You and Me Forever (A Niall Horan fanfic)

When Ariana Styles (Harry Styles twin sister) finally meets her brothers band one direction after % years of schooling in america. one of the boys stands out to her the most the one and only Niall Horan. They start to become very close. Maybe too close for her brother to handle! will this ruin their relationship? Or will Harry have to respect his sisters decision by having a relation ship with one of his best friends? but what will happen at the end of the summer when she has to go back to America?