The story is about Hiromi Oka (岡ひろみ Oka Hiromi), a high school girl who struggles to become good at tennis. Hiromi starts playing tennis at her school, Nishi (西高), because she is fascinated by Reika Ryūzaki (竜崎麗香 Ryūzaki Reika), an older girl who is the best player in the team and is nicknamed "Madame Butterfly" (お蝶夫人 Ochōfujin) because of her grace on the tennis court. The team gets a new coach, Jin Munakata (宗方仁 Munakata Jin), who sees potential in Hiromi and trains her to become a great tennis player.

Hiromi struggles to overcome her mental weakness. Later, she falls in love with another tennis player, Takayuki Tōdō (藤堂貴之 Tōdō Takayuki), but coach Munakata tells her not to get too involved and that she should forget him and work on her tennis skills. Hiromi often loses confidence in her playing abilities, but with the support of her coach and her friends she overcomes her anxiety. By training herself to become a better player, Hiromi grows into a mentally stronger person. Her enthusiasm, her love of tennis and the support from people around her helps her to become one of the best players in the world.