The movie is based on a Vocaloid song project (Kokuhaku Jikko Iinkai Project) by a famous Japanese music group called HoneyWorks. The characters and hints of the story have been released in separate music videos, songs and illustrations since 2014. All of these were made by the five member group HoneyWorks. Some of the songs - such as Byoumei Koi Wazurai - were used as part of the movie's soundtrack.