In the near future, advances in technology and virtual reality have changed Japan, leading to many applications in the real world, such as security, businesses, transportation and even the development of a new sport called Circlet Bout, an event played by many schools across the country. Mixed Reality, the technology used in Circlet Bout, can be used to store data about the players, such as their academic skills, and generate weapon for matches.
By sheer coincidence, Yuka Sasaki gets involved in a Circlet Bout match against Chikage Fujimura, the best player in Japan. Despite her inexperience, Yūka holds her own against Chikage and both players develop a respect for one another. Yūka gets inspired to become a CB player and, two years later, she transfers to a school in Tokyo in order to accomplish her dream. Upon her arrival, she finds out the school's CB club has been closed down, so she sets out to re-open it with her new friends.