The story is about late teens Light Yagami who is either in high school or going into universety (I forget), one day he sees a book fall from the sky and goes to check it finding it to be the death note. He tests it out on a guy whos hitting on a girl and kills him, Light is scared but then he meets Ryuk a shinigami who tells him about the death note. After that he proclaims himself to be god and starts killing crimnals. But the polcie catch onto it and get a top detecive L who is determained to get Light, it also doesn't help that Light's father is a cheif policeman. During the course of the story he gets a girl called Misa with a death note who love him and agrees to help him, many things happan and it is quite good.
I guess people enjoy it so much because there is an elimate of suspense and the first few episodes are quite dark, persanally I think that halfway through the story goes downhill but the first part is good. But it is sad parts of it are sad and it is about killing people so just a warning be prepared.