As the older sister of four brothers, Mihoro is used to quite a lot. It's no surprise that she generally has a rather sisterly relationship with boys. Romantic feelings? Not a chance! This doesn't change even when she meets the one-year-younger Miyao. The two quickly become friends, but nothing more will happen, as Miyao soon realizes. However, the self-assured young man is not willing to accept that and straightforwardly tells her, "Hey, I may be younger than you, but I'm not your brother!" Will he be able to win her heart this way? A lighthearted romance between an older girl and her younger friend.