Akari Mamiya is in Year 1 at Tokyo Butei High School. Although she is currently in E Rank, her goal is to become a BUTEI like Aria Kanzaki, an Upperclassman in Year 2. In order to receive training from Aria, Akari submits a request to become Aria’s Amica.

Kyochikutou’s sister, Suimitsutou, goes on a rampage while demanding to have her sister returned to her. Aria, Akari and the others work together to bring her down.