Summer vacation has begun at Binan High School, and Aso Sorata returns home with the gluttonous Oshamanbe, whom he caught with mountain delicacies. Waiting for them in their hometown are Aso's three younger brothers. Aso is treated as the youngest in the Defense Club, but in his hometown he shows off his big brother side, but for some reason, the second brother, Tonta, rebels against Aso. When he runs off during a sibling fight, he is transformed into a monster by the Conquest Club, who happen to be nearby for summer vacation! What will become of the brothers' bond? And when will Unzen and the others get involved? (thetvdb.com)