The Caerula Adamas plot a way to destroy the mysterious Battle Lovers. They also want to destroy the Defense Club, so as to cut down on club expenses. Thus, they declare that if the club members' scores on their final exams do not meet the average, the club will be dissolved. The Defense Club reluctantly gets to studying. Meanwhile, the student council also tries to scout the financially savvy Naruko to be their treasurer. When Gero offers him a salary during negotiations, Naruko casually agrees to leave the Defense Club. Soon, a monster appears, and the four remaining Battle Lovers must struggle to defeat it themselves.
The riddle I've been puzzling over 
since third grade is solved!
Die Frage, die ich mir seit der dritten
Klasse stelle, ist endlich beantwortet!
¡La duda que tenía desde el 
tercer grado por fin fue resuelta!
¡La duda que tenía desde 
tercero por fin fue resuelta!
Je me posais cette question
depuis le primaire !
Finalmente ho risolto l'enigma che mi stava facendo
 scervellare dalla terza elementare! Evviva!
Esse enigma que venho tentando resolver
 desde a terceira série, finalmente se resolveu!