Anohana the Movie: The Flower We Saw That Day (Ano hi mita hana no namae wo bokutachi wa mada shiran

Because of an accident during their childhood, 6 friends hearts were closed shut, and they grew apart from one another. One summer day, their friend who passed away in the accident appears before them. But, she cannot remember the reason why she came back. The friends meet once more to figure out just what her reason is.