Onee-chan ga Kita Anime Details and Episodes The story revolves around Tomoya Mizuhara, a 13-year-old boy who suddenly gains a big sister when his father remarries. 17-year-old Ichika is a little… Series info · Watch free · Trending anime · Airing schedule FormatMangaStatusFinishedScore57/100SourceOriginalCountryJapan Comedy · Slice of Life 4-koma · Seinen · Male Protagonist Onee-chan ga Kita (Adaptation) She's Adopted a High School Boy! Ichika Mizuhara · Tomoya Mizuhara · Eiko (Supporting) · Yoshiko (Supporting) · Utako (Supporting)