Once upon a time, there was a hero who protected the Earth from a great crisis... And now, in the face of another crisis, a new hero is born from Binan High School's "Earth Defense Club"! ...Huh? Who were those former heroes? Well, it was "those guys", "those guys". ...Huh? Why are you blurring out the names? It's a multi-verse setting, so mumble mumble... (vague)　Anyway, the new defense department - Unzen Shinkuro ,Sukayu Narushi, Unohana Sousuke, Oshamanbe Ushio and Aso Akuta.

With the help of the feline science of the mysterious future cat Nuru, the five members of the Defense Club have become the "Hi-CARA Romantic Squad" and successfully defeated the monsters plotting to take over the Earth. Then, before them appears the "Ban-CARA Avant Guard Corps", an Earth Conquest Club led by the mysterious prairie dog Master Kyan. Their true identities are none other than Doumeki Straight, Nyutou Samon and Nekoma Tasuku, roommates at the Kurotama Dorm and members of the Binan High School Student Council. With lies and enemies under the same roof, it's impossible for something not to happen... right?