The key to this movie's success is probably the interest in the time period. Sure, there's some good laughter and mystery, but the settings are probably the biggest pro for the films. I didn't take too well to the whole plot of the movie. Maybe it was a well-thought out movie, but I didn't quite take to the ideas. It seemed as if someone just asked their child what would make a good movie. Then the child begins to create a elaborate scheme.
Of course, the good guy has to win. So the plot jumps hurtles and sidesteps as well as it can to allow the good guy the win. I don't really enjoy these types of movies. The ones that go against the odds without some realism to them. None of the heroes were really lost, so that tips the scales into the make-believe world.
For me, I'd have to say the film wasn't awful, and it wasn't great. I'd give it a 7/10.