Koukyuu Days - Shichi Kuni Monogatari

From Day of the River: Hisui, who works for the Golden Rooster Theatre Group, was orphaned when her parents were killed in a giant massacre ten years ago and her brother Kohaku was abducted. One day, she is summoned to the Emperor's palace and only agrees to go because she suspects that he is behind her brother's disappearance. Inspired by "The Story of Saiunkoku".