Kawashima Manaka is a high school girl in love with her childhood friend and classmate, Eguchi Ei. Kawashima continues to think wholeheartedly of Ei, but then another heroine, Takatobi Ayame, transfers to the school. However, unlike Kawashima, Ayame bumps into Ei on the way to school on the morning of her first day at the new school, and even gets lucky and lewd, making her the undisputed winner. Kawashima is disheartened, but the story's minor protagonist, Kimura, will do his best to transform Kawashima from a losing heroine into a winning one...!?