There's a new student at St. George International School, and soon he becomes one of the most talked-about students. Even though it's an international school in Tokyo, Japan, the new student (Yonogi Dai) is a Japanese boy. Dai was raised in the US and recently came to Japan for the first time.

Dai turns out to be a distant person, uncaring about other people and those who want to be his friends. He looks quite cute and gentle but he's actually unsocial and can be harsh. Jerry Morton who's very popular and well liked among the student just wants to ignore this cold Dai, but being the kind hearted (and nosy) boy that he is, he begins to approach Dai.

Jerry and Marty and their other friends soon find out that indeed Dai is rather difficult to deal with, but it doesn't take long before Dai becomes their friend. However, sometimes when they feel that Dai is getting closer to them he would say or do something that shows that he doesn't really think them as his close friends.

The story then begins to unfold itself. Dai's new friends start to discover the truth about the mysteries surrounding Dai. Why he's in Japan, about his family, about Ken in the States who seems to be the only one he's having personal contact with, and about his relation to a very famous game, "Sabbath Child". They discover the real Dai just like Dai discovers his true friends in life, and also himself along the way.