The story revolves around the protagonist "I" and the murders and mysteries he encounters. He tries in vain to stay out of the story, but instead he always gets dragged into the center of everything. Even though it seems that he contributes a lot, he always finds out that whatever he did was meaningless in the end.
Light Novel adaptations have had something of a poor reputation over the past couple of years in anime. For every actually good one, there are 5-6 terrible highschool harems led by Yuji Everylead the Bland. But this upcoming Fall 2016 anime season looks like it might be the exception....maybe?