Okay, so this is not a masterpiece and it is hard to follow a movie like The Dark Knight but it is a fun flick especially for fans of the series.
It was not quite as supernaturally driven as some of the X-files episodes but it did have a psychic which was why the FBI wanted Mulder(David Duchovny), who they betrayed, to come back. To locate him, they will need Scully(Gillian Anderson) as finally it is made clear, though not immediately, that Mulder and Scully are together as a couple. They may fight it at times but they belong together and more alike than they realize. Mulder in this movie is far more resolved with who he is than Scully. In the end she seems to realize she wants to believe too.
Basically this movie is an X-file episode on the big screen. The mystery is entertaining as always, the dialog between Mulder & Scully is smart and nostalgic, the music is updated and improved by composer Mark Snow, and it offers a resolve for Mulder and Scully that the end of the series and previous movie lacked. If you are an X-files fan go see it and stay through the end credits for a giggle... but if you were not a fan of show this is probably not for you.