After returning from her advanced studies with Celestia, Twilight finds a strange and mysterious book with power over death itself. Soon she finds herself haunted by a strange creature that only she can see, and a nagging urge to test out the power of the book for herself. Driven by the spreading corruption, Twilight begins down a dark path that enevelops not only herself and her friends, but all of Equestria.

(This story does change some of the rules of the death note, though i will try to stick to the rules of it as i can)

((You can find the cover image here http://www.everypony.com/forums/attachment.php?attachmentid=5418&d=1345121575, I take no credit for making it, but it was the first thing that came up when i google imaged Death Note+My Little Pony))