As IMDB states, an attempted assassination is told and re-told in different perspectives, each adding to the story and making it that much more complicated and an edge-of-the-seat thriller. Very good movie.
After Inconvenient Truth this is the next movie on global warming that I have seen. Very well depicted. Has lots of thriller-moments (not needed actually) which makes the movie an edge-of-the-seat. A sci-fi but very close to reality.