Inspired by Saiunkoku Monogatari. 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. (Source: Day of the River)

Koukyuu Days has been digitally published in English as Harem Days: The Seven-Starred Country by Media Do International/Akita Publishing since February 13, 2018.