Kazuhiko lost his parents in an unexpected accident on the way to a family trip, and because of that accident he lost his memory too, having just fragments.
He was invited by an old friend of his deseased father to live in his house, with his family. And he became like an older brother to Masako, the daughter of that family, one year younger than him.
The time passes in that house, with him living a peaceful and happy life. But one day, Kazuhiko witnesses something completely unexpected. His old memory starts to gradually come back, and he starts to going mad.
