In the virtual realm of OZ, a popular online world, users engage in various activities through personalized avatars amidst tight security and encryption. Society heavily relies on OZ, even tasking it with retrieving the unmanned space explorer Arawashi. Kenji, a gifted 17-year-old and OZ moderator, is unexpectedly pulled into an adventure by his crush Natsuki, posing as her betrothed. As he deciphers a cryptic message on his phone, intended for him to solve, Kenji inadvertently triggers a perilous chain of events with his mathematical prowess, jeopardizing Earth itself.