A 16-year-old boy named Shurato and his friend Gai happen to be drawn into a gigantic ball of light while competing in the final match of a martial arts tournament. When they regain their senses, they find themselves transferred to a mystic heavenly sphere with a divine atmosphere. It's soon discovered that Shurato used to be the governing king of this world and that he has only been brought to his original state. Shurato is shocked as Gai suddenly turns hostile. After this unfortunate incident, a spectacular yet fantastic drama develops involving the two.

Ichinomiya Kantarou grew up with the ability to see demons, but was isolated and bullied by others who did not share the same gift. Instead, he became being friends with the demons, gaining a great attachment to their existence. One day, Kantarou was told about the strongest demon, the one known as the ogre-eating Tengu. Amazed by the news of his strength, Kantarou vowed to find this demon who was far stronger than any other, deciding to call him Haruka when he did so. Since this time, Kantarou searched far and wide for the ogre-eating Tengu with no luck, making his living by becoming a folklore writer and demon-buster. On a particular job, Kantarou had finally found news of a nearby shrine supposedly the place where the ogre-eating Tengu was sealed.

Kyon has found himself dragged through many adventures as of late—all because of the SOS Brigade club and its excitable leader, Haruhi Suzumiya. He has stopped believing in the supernatural long ago, but after being forced to join this club based solely on that, he has seen things that cannot be explained logically. Joining Kyon on his various misadventures is the shy and soft-spoken Mikuru Asahina, the bookish Yuki Nagato, and the ever-cheerful Itsuki Koizumi. Whether it is summer vacation or a school festival, things involving their club and Haruhi herself always end up becoming strange. [Written by MAL Rewrite]

Yamato Akitsuki travels to Tokyo alone to study in one of the high schools located within the area. He lives in with his aunt who operates a public bath solely for the ladies in the local district and begins his normal high-school life. One day, he chances upon a girl in school and is immediately mesmerized by her beauty. He is shocked when he realizes later that the girl, Suzuka, is actually living next door to him. From then on, Yamato's ordinary life begins to change little by little.