Seven is about two detectives. One is ready to retire and the other is at the start of his career, and follows their attempts to capture a killer who is using the Seven Deadly Sins as his scenario.

Detective Somerset (Morgan Freeman) is a veteran cop who lives a lonely life in a furnished room (I think). He is partnered with the young Detective Mills (Brad Pitt), newly tansferred into his district. They investigate a gruesome murder, in which a fat man whose hands and feet were bound, and was forced to eat himself to death. His crime was the crime of Gluttony. Soon, they are investigating equally inventive murders involving the other deadly sins. Somerset thinks the killer is using his crimes to preach a sermon.

Somerset feels the killer is using books to inspire his crimes. A break in the case comes when Somerset's hunch that the killer might have a library card pays off. It becomes clear that the killer is preaching directly to the two detectives. The rest of the movie I don't want to spoil for those who haven't seen it.

The movie is a dark, grisly, and disturbing film of the highest order. It is extremely well-made and relentless in the way it shows the details of the crimes.