Histoire
"Kei-chan, see you tomorrow!" — That promise was never fulfilled, and young Kirishima Keisuke was separated from his only close male friend, Maa-chan. Then, ten years later, the person who arrived due to their parents' remarriage was none other than Maa-chan—now Masaki—who had grown into a charming and outgoing beautiful girl! While Keisuke, who had always mistaken her for a boy, is confused, Masaki begins interacting with him even more closely than before, as though they were siblings. Playing games together, eating meals together... and even trying to bathe together!?
Synopsis via AniList (en anglais).
