Binan Koukou Chikyuu Bouei Bu Haikara!
It's the Taisho era - a time filled with the scent of romance, and people's hearts are still filled with compassion.
Unzen, Sukayu, Unohana, Oshamanbe, and Aso are all ordinary (?) male students at Mayunan High School, who spend their days lazing around in the clubroom of the "do-nothing club" Earth Defense Club, and live together in the Kurodama dormitory.