Nao Amemiya, an ordinary senior high school student, has a childhood friend. She has known Yuichiro, who is six years older than her and lives next door to her in an apartment, for 10 years. Am I not indulging in a cozy relationship that is both friend-like and family-like? The troubled Nao decides to move away from Yuichiro, but...?

They are childhood friends even though there is a slight age difference. This is their little love story, interwoven between three groups of six friends.