Light Turner is an unhappy high school student who tries to do the right thing. When we first see him he interrupts the bullying of a girl, only to get beaten up. Then, from the sky, falls an old leathery book titled "Death Note". He looks at it and soon a spiky demon named Ryuk shows up and explains things to him. The book has the power to kill anyone whose name is written down in its pages. The only catch is that he must have a clear picture of the person's face and also know their real name. Ryuk convinces Light to try it out, so the first name he puts down is the bully who is terrorizing the school. He has him die by decapitation. A minute later Light looks out the school window and sees a car accident in which a ladder flies off a truck and gorily decapitates the boy. It works!
Then Light gets the idea to "go bigger" and begins writing down the names of world terrorists. The authorities think the mysterious slayings are due to some new group called Kira, which Light has invented. The death toll quickly rises to over 400. This gets the attention of the authorities who want to stop it because he's a vigilante. To complicate things, Light's father is a detective and is soon on the case when it's discovered that "Kira" lives in town. Who finds this out? A weird investigator named "L", who seems like some kind of autistic savant. Light also lets his girlfriend in on his secret and she has a desire to own the book because she comes to believe Light doesn't have the balls to do what needs to be done. She's bloodthirsty and wants to kill innocent people, something Light will not do.
I found the first half of this movie great. It's like a John Hughes Film crossed with Final Destination. However, once the character of "L" is introduced, the storyline and whatever plausibility is stretched and it becomes a bit convoluted and "cartoony", more of an action film than a horror film. Which makes sense since this movie is based on an Anime series of the same name. Still, it is entertaining and well produced. Recommended.