This is the story of the trials that Kyon must endure to placate Haruhi.
This is the story of Kyon, wandering trials beyond comprehension for no clear reason.
This is the story of discovery of self, and determining what your meaning is in a meaningless world.
Okay — actually, it's all of those. And a lot
It's very difficult to encapsulate this entire story without devolving into a multi-thousand-word review about all of the little details, but....
Some readers may be annoyed at a number of the reveals through the story (I myself was), particularly the author's early explanations of what the ending would be, and how Kyon himself was handled. That's not to say it's actually bad; the author was being remarkably clever and technically honest!
But moving past that, this is an amazingly (sometimes painfully!) evocative piece, with a conclusion that astounded me by being uplifting in the face of what the story was. Buckle in for a surprisingly hard-hitting ride ... but one that stays true to what it is, and still delivers what I think is the best ending possible. An excellent, powerful story, well worth the time to read it (IMO).