The story begins with Hazumu, the main character, as a boy, who always seemed to have a crush on his friend and classmate Yasuna Kamiizumi ever since he first met her. He was not very masculine in either his appearance or his actions, and so as a child he would get teased for being so feminine. In addition, several flashbacks have been featured in both the manga and anime featuring Hazumu dressed like a girl at a young age. Whether he wanted to do this of his own accord or his mother just dressed him up is never specified but regardless he didn't seem to be bothered by it; indeed he was shown to enjoy it.
Once in high school, he confesses his love to Yasuna one day, but is rejected. Afterwards, he climbs the nearby Mt. Kashima to clear his feelings. He is fatally injured by an alien spacecraft crash-landing on the mountain. In an attempt to rectify the accident, the alien pilot revives Hazumu but inadvertently changes his physical sex in the process.
After the change and initial shock of those who know Hazumu, it is shown that she has a personality that is very effusive, expressive and quite sensitive which makes her fit well as a Japanese girl. Hazumu ends up becoming more feminine as time goes on, which is shown through her actions, mannerisms and personality. One exception to this, however, is that she never got over referring to herself using the term boku (僕), meaning "I", which is usually only used by males in Japan.
Hazumu, as an amateur floriculturist, loves plants (more specifically flowers), and is very knowledgeable about them. She is in the Gardening Club, and takes care of a large number of plants around the school campus with the other members though is seen doing most of the work throughout the series.
When the manga and anime versions of Hazumu's character are compared, it's shown that Hazumu in the anime is much more subdued and reserved when confronted with danger, which makes her depend more on the help of others. In the manga, she's much more of a stronger female character and doesn't get scared at talking back with a smart retort.