7 years ago, Mukai came up with the idea of making the book into a real-life movie and participated actively in the production along with the director Fukagawa Yoshihiro who was responsible for "Kamisama no Karte" and Yamamoto Mutsumi who wrote the scripts for NHK dramas "Gegege no Nyoubou". When asked about this, Mukai said that this has been a dream of his since he became an actor especially since he wouldn't be where he is now without his grandparents. In addition, he hopes that the story of overcoming the odds will inspire people to reflect on their own families and ancestors.
As for working with Ono, Mukai said that her presence alone lightened up the atmosphere of the filming and he was glad to be able to work with her. In response, Ono praised her co-star for being gentle on people but demanding about acting so he was always trying to explain how things should be done since he had first-hand knowledge of the story. She also revealed that when she got the offer, she agreed to it immediately upon hearing that this is a Mukai Osamu project.
The movie will be shown in cinemas from 24 June 2017.