Memento chronicles two separate stories of Leonard, an ex-insurance investigator who can no longer build new memories, as he attempts to find the murderer of his wife, which is the last thing he remembers. One story line movies forward in time while the other tells the story backwards revealing more each time - quote from imdb

this movie is a good example of post modern media as the film is set non linear

in linear order the film would play out with first his wife being assulted and raped and he the cracks his skull and suffers from memory loss. lennys wife doesn't beleive him and he gives her too many insulin shots and kills her.