When good-for-nothing employee Daichi is attending to a backlog of work, a frightening game of tag targeting people with blood type B begins.

Sakai's Happiness is a humorous and bittersweet portrayal of an ordinary family dealing with the challenges of everyday life.

Set in the year 3000 in New Tokyo where this time round, human beings with blood type B are being targeted.

While researching a story on a school for problem children, Nakahara meets Emi, a college volunteer with a compelling tale of her own. After overcoming her initial reluctance to open up to the writer, Emi talks about her busted leg and her childhood friendship with the chronically ill Yuka.

After his parent's divorce, Kazuo Saito moves with his mother from Onomichi and must leave his girlfriend behind. At his new school, Kazuo is surprised to reunite with his childhood friend Kazumi.