If you've read the Dan Brown books, then, the MASSIVE SPOILER WARNING will be moot for you because you pretty much know who the bad guy is and have a more or less good idea of what's supposed to happen in the movie. If you've never read the books, then okay, I say again: SPOILERS FOR THE MOVIE.
Honestly? I went to see this movie because Ewan McGregor looks HOT in a cassock....
( So, about three things I was absolutely sure about... )