With the school's yodelling club abolished, the Gappori Company seek to take over their clubroom to expand their operations, but are met with competition from another group, Gamitsui Corporation, led by Hana Akinai, who want to use it for their 'Detention Club', where they use their feminine charms to get boys to study. Upon investigating, Kaito and the others discover the girls of Gamitsui are using their whiles to receive presents from boys, which they pawn to bolster their funds. When some of the customers take argument upon not getting dates like their promise, Hana beats them in Hero Battles using her hero suit, Shadow Kitty, forcing the losers to become regular customers. Learning of this, Kaito challenges Hana to a Hero Battle with the yodelling club's room on the line. Managing to prove resilient to Hana's womanly charms, Kaito overcomes her attacks and wins the match. Despite her loss, Hana becomes determined to participate in the Hero Wars and find a boy that can make her happy. However, Kaito and the others discover that the yodelling club has reformed, putting their efforts in vain.