Jindai High is a school in Tokyo, Japan. Once a normal school occupied by normal students and teachers, gets turned upside down by a particular soldier that has an obsession with guns and blowing things up. In short, Sousuke's basic motto is "When in doubt, Blow it up." Because of this theory, Sousuke destroys parts of the school many times, including blowing up lockers from suspicious notes, making traps to keep meat buns safe from any sneakers, and firing bullets on just about anything suspicious.
Jindai High School sure has become a lot less boring, but time is never boring when you have a guy like Sousuke Sagara around. Many guests often come to the school. Teletha Testarossa visits school for a week, where she causes some emotional turmoil for Chidori and friends.
Another conflict often dealing with the school is the clubs. Due to the shortage of space and recreation, many of the clubs must be dealt with by the student president, aka Chidori Kaname. And wherever Kaname goes, so does Sousuke. Club conflicts range from Martial arts to the Social group flirting contest, down to the rugby club.
The building itself comes a war zone occasionally through out the story, most of the time the war being between Kaname Chidori and Sousuke Sagara and students, but there are times when Mithril and Unexpected Terrorists decided to ensnare the school as their ground for exchanges. Such is the time of the episodes dealing with Behemoth, where Sousuke is forced to trade the boy for either Tessa or Kaname.