The first series, 13 volumes -- Ichirō Suzuki, a straight young man who becomes besotted with another guy, Yūki Sato, convinced his bishōnen love is a girl trapped in a boy's body. Interestingly, author Hiroya Oku is one of the characters in the story, the best friend of Satō. The first three volumes of this series collect Oku's early short stories, including prototype versions of both Hen series. (From wiki)