the death note is the notebook of death. You can kill someone by writing their name (if you know what it is) and knowing what they look like. If you start killing a lot, the great detective L (his real name is Lawliet, but he hides it) will hunt you down. L likes sweets, is competitive, calm and wants justice to be done. the shinigami Ryuk likes apples and is impartial. Besides you, Misa is the only one with a death note and she also has shinigami eyes, being able to see people's names