The Dark Knight Rises: Prologue app is exclusive for Nokia Lumia phones and shows events before the movie
prior to the beginning of the movie. The Dark Knight Rises: Prologue app is a special type of comic called a "motion comic" as the images scroll and pan right on the screen of your Nokia Lumia device. At 52MB, the app is pretty hefty, but is well worth it for Batman fans.
If you haven't seen the movie yet, it is still ok to view the app; Remember, as a Prologue, the scenes and dialogue from the comic take place before the action in the movie occurs. If anything, viewing the app before you see the film might help you better understand the movie.
The Dark Knight Rises: Prologue is available from the Nokia Collection in the Windows Phone Marketplace.