The first-year students participate in an annual treasure hunt event, with Eruna paired up in a team with Otone, assisted by a Mecha Bimii. As Eruna clears the first set of checkpoints, Otone expresses her disinterest in teaming up with her and runs off. When Eruna injures herself after slipping off a cliff edge while searching for her, Otone takes her to her secret hideout to treat her injuries and have teatime with her. Things soon become hectic when Mecha Bimii transforms into a giant mech and goes on a rampage, but Eruna and Otone manage to use their combined abilities to make it out safely. Afterwards, as Otone agrees to help Eruna form her club-in-progress, Seisa grows concerned after witnessing Otone's Anticomplex ability.
High school student Eruna Ichinomiya enters the Mikagura Academy dreaming of a boarding school life filled with beauty. However, Eruna finds out that in the culture clubs, there is a rule that battles that are fought with special powers decide a club representative's treatment. Through various circumstances, Eruna becomes a representative of a club, and is thrown into the fray.
