Death Note(aka DN) is a very popular manga/anime.
Its about a boy named Light( or Raito in the Manga) Yagami who is the probably the smartest student in all of Japan. Light finds a suspicious black notebook one day called a "Death Note" and takes it home. The intructions say "The human who's name is written in this notebook shall die." Light is curious and tests it. When he finds out that the notebook works, he decides to rid the world of all evil. (One of his famous quotes are "This world is rotting.") But the police hear about how all these criminals are dieing of unnatural deaths (hearts attacks at young ages, etc.) and the World's Best Dectective L tries to track down this murder, or "Kira".
Death Note is a great manga and an awsome anime! If you don't own the first book, you can read it online:
http://www.onemanga.com/Death_Note/and here is the link to the first episode in English (for some reason i cant find the english verison for ep. 1 on youtube, but the rest of the eps r there!)
http://www.animefreak.tv/watch/death-note-episode-1-english-dubbed-online-freeand thats pretty much it!
I totally recommend reading and watching this series! Very good !I give it 5 stasr!
oh and i rate it 13+ cuz they do curse and use violence so he parent permission if younger! :)