Kenji Koiso is a 17-year-old math nerd and OZ moderator who is invited by his crush Natsuki Shinohara on a summer trip to Ueda, Nagano. But unbeknownst to him, this adventure requires him to act as her fiancé. Shortly after arriving at Natsuki’s family’s estate, which is preparing for her great-grandmother Sakae’s 90th birthday, he receives a strange, coded message on his cell phone from an unknown sender who challenges him to solve it.
The real-world segments take place in Ueda, Nagano. Ueda was formerly governed by the real-world Sanada clan, which serves as inspiration for the fictional Jinnouchi family. According to an interview, Director Mamoru Hosoda made multiple trips to his wife’s family’s home in Ueda before and during the production cycle. The OZ sections take inspiration from Nintendo user interfaces and early metaverse games like second life and mixi.
An official print map was produced at some point.
