Yasuko to Kenji

When the parents of Kenji and his younger sister Yasuko died 10 years ago, he decided to leave the motorbike gang, he was the leader of, to start drawing shojo mangas under a pen name. Because those mangas are selling quite well he can take care for Yasuko. Only when Yasuko gets into trouble, Kenji is changing back to the violent leader of a motorbike gang.
In school Yasuko falls in love with Jun Tsubaki, who looks very good and is popular. His sister Erika was a leader of a motorbike gang just as Kenji, but is running a flower shop nowadays. When Jun has problems, Erika helps him out with a little bit of violence, too. Since her time in the gang, Erika fell in love with Kenji, and since Yasuko and Jun are getting along well, those two meet again...