Prism (Higashiyama Shou)

riding high on the memory of a boy named hikaru with whom she spent a day during her last year of grade school, megu went through middle school without romance. now that she's a high school student, she has decided she is finally completely over her first love and can look towards the future. shikashi! megu meets a pretty girl on her first day of high school who gives her a big hug, and her name is hikaru?!