At her grandmother’s request, Mari Wakatake grudgingly begins attending the Kaiho Academy.  Upon her arrival, the headmaster is informed that five years ago, Mari was in an accident and lost all of her memories. Mari is shown around the school by Michiko Kozuki, a classmate. At her dorm, she is introduced to Hagino Senkoji, a strange girl who begins to choke Mari after greeting her. Michiko comforts Mari and tells her that she needs to get better acquainted with Hagino. Things do not go so well at dinner, or in the middle of the night when Mari follows Hagino outside and sees a alien ship. …