Following their battle, Mamori and Mirei are restrained by two other Liberators. While Mirei is locked away in a disciplinary room, Mamori wakes up in the care of Kasumi Shigure, commander of the Welter, who explains that all the girls on the island are carriers of something called the Armed Virus, who are divided into Exters, who can transform into weapons, and Liberators, those who can wield them. Charlotte Scherzen, one of the Liberators from before, then informs Mamori that she is to undergo a wedding ceremony to find a suitable Liberator as a partner. As Mamori is arranged to be partnered with a trainer named Tomomi Nukui, Meifon Sakura, a girl who enjoys running bets on Liberator fights, follows order to set Mirei free, allowing her to come to Mamori's rescue. Undergoing a Drive once again, Mamori and Mirei escape to the beach, where they properly introduce themselves to each other.

Meifon works with her partners in crime, Hyouko Yundou and Futaba Kirii, to steal more goods from Veste while also making money from gambling. Feeling she can make a killing from bets, Meifon arranges for Mirei to enter a beauty pageant being held at the Mermaid Festival. On the day of the festival, Charlotte gets chosen as the winner, with Meifon deducing that Hyouko and Futaba had switched out the ballots in order to kiss up to Charlotte. Discovering what had happened, Mirei and Mamori face off against Hyouko and Futaba's decoys, while Meifon uses her love of money to transform herself into an Arm to fight against the real thing, coming out victorious. With Hyouka and Futaba's crimes exposed, the pageant is revoked while Meifon delivers the prize to Mamori.