Based on a children's fantasy novel written by Hinata Rieko and illustrated by Yamada Akihiro.
The first episode received an advance release on Wowow's YouTube channel on January 6. The regular TV broadcast started on January 14. Holp Shuppan have published four volumes between December 2018 and September 2020.
The screenplay was written by Mamoru Oshii, writer and director of Ghost in the Shell (1995)