Hiromi Oka, a first-year student at West High School, joins the tennis club admiring Reika Ryuzaki, aka Mrs. Butterfly, and senior Todo. She is a complete beginner, but as soon as she joins the club, the devilish coach, Munekata, sees her talent.

High school freshman Hiromi joins the tennis club because of her admiration for Ryuzaki. Ryuzaki is a senior, who's the best tennis player on the team and also nicknamed "Ochōfujin", ("Madame Butterfly"), because of her elegance on the tennis court. However, the new coach, Jin Munakata, wants the inexperienced Hiromi to play in a forthcoming tournament.