The manga is a prequel to Hakuri’s One Room of Happiness (SACHIiro no One Room) manga, and features the detective character Hijiri Matsubase as the protagonist.
Hakuri launched the original One Room of Happiness manga on pixiv and Twitter before switching it to Gangan pixiv in February 2017.
Square Enix published the first volume of the manga in September 2019.
Square Enix will ship the manga’s ninth volume on May 21.