Inseparable middle-school best friends Haruka Takayama and Yuu Sonoda enter high school expecting more of the same, only to be seated on opposite ends of the same classroom. To keep their bond from fading, the two start sneaking off between classes to share quiet kisses in empty rooms and stairwells. As they juggle that secret habit with classmates Kotone Noda, Shizuku Minami, Kaede Ikeno and Yuzu Iizuka, both girls begin to wonder what their kisses actually mean to them.