First of all this is a very well written Light Novel.

I read this in English and not in Japanese. The story is very interesting that I end up reading it in one sitting. The story is about a boy named Masaya Kishitani that commit a suicide that left a will that says "Taku Sugawara is the devil. Nobody should believe his words" and his sister Sanae Kishitani try to unfold the reason of her brothers suicidal death. The way the mysteries were unravel was outstanding.

The aspect of the story that I like so much was the way it tackled a very delicate topic like "bullying".

Give this a try, It's a very short but satisfying read.