Aki and Sora Aoi have been unusually close since childhood, and as they come of age that closeness turns into a secret romantic and physical relationship they keep from the rest of the family. Sora's twin sister Nami, with no idea what is happening at home, tries to set him up with her best friend Kana Sumiya while holding on to feelings of her own. The tangled attractions inside one household drive this explicit adult manga.