Suzumiya Haruhi is a charismatic high school girl with a carefree personality and a very egocentric way of thinking, that she underlines upon enrolling at school by announcing: "I have no interest in ordinary humans. If there are any aliens, beings from the future, or espers, come see me. That is all!"

This makes quite a few heads turn, but Haruhi is dead serious, as she soon proves by establishing the SOS Dan.

As it turns out she has the unimaginable power to change the world, but is completely unaware of this power, and so she is also unaware of the effect her power has on the outside world. The cynical Kyon does not become Haruhi's best friend and first member of the SOS Dan out of the kindness of his heart, but initially out of self preservation, since he quickly understands the possibly catastrophic implications of Haruhi's powers. Luckily he seems to have the gift to keep her more outrageous schemes in check...

[Source: AniDB]