Kyon is an ordinary freshman high school student who, self-admittedly, has given up his fantasies of espers,
time travelers, and aliens as he left middle school. However, sitting
behind him is the beautiful, intelligent, and eccentric girl Haruhi Suzumiya,
who in her class introduction blatantly states her singular desire in
meeting aliens, time travelers, sliders, or espers. Interested, Kyon
starts trying to make small talk with her before class, eventually
leading to normal conversations with Haruhi. One day, after making a
comment about Haruhi's displeasure with the available school clubs, he
finds himself dragged into membership of the newly formed Spreading Excitement All Over the World with the Haruhi Suzumiya (or SOS) Brigade.

Haruhi quickly claims the Literature Club's room and its sole member, the silent bibliophile Yuki Nagato as property of the SOS Brigade and "voluntary arrests" the timid but cute Mikuru Asahina and the polite, smiling Itsuki Koizumi
as the club's other two members. As the story progresses, however, Kyon
finds that each of these supposedly "helpless victims" are actually
agents of fantastic organizations who have been sent to monitor Haruhi,
who they explain as having superhuman abilities of manipulating the
universe. Haruhi's unawareness of her powers means that she
unconsciously creates a new universe — one more to her liking — and
attempts to switch over whenever she becomes bored or otherwise
dissatisfied with reality. To prevent this, the members of Haruhi's
club spend their time trying to keep their god-like leader entertained,
hold her powers in check, and maintain the illusion of a normal life.