Seishun For-get!

From FairGame: "Live with Sincerity" is Natsuki Taiyou's motto. It's first day of high school and on the way there Taiyou meets Hinata. He fell in love with her at first sight and suddenly confessed to her. She answered yes and ran away without saying who she was, but it turns that she was his classmate. Taiyou felt a destiny between them. However, on the next day, she doesn't remember who he is. Why, could it that be...?