"National Treasure: Book of Secrets" is on par with the original "National Treasure" movie. The first was written as an American response to the book "The DaVinci Code". "National Treasure" was actually much better than the "DaVinci Code" movie. This movie holds up nicely to the original. Better yet, you don't have to have seen the original to enjoy this one. Really, outside of being aware that there was a previous one you don't need to know anything about it.
In this movie an ancestor of our hero (Nick Cage) is accused of planning the assassination of Lincoln instead of foiling a plan by the Confederates to find a missing treasure as was previously thought. Cage goes on a mission to find the truth and clear his ancestor's name. It's not as heavy on the "the clue is hidden in George Washington's hair in the dollar bill" as the first, but there's still lots of hunting for clues on monuments and cracking codes. This includes a raid on the Queen's office in Buckingham Palace, sneaking about in the Oval Office, kidnapping the President, nabbing the President's secret book, and searching for the Lost City of Gold in the Dakotas.
There's a lot of nonsense in some areas, but in other areas they seem to have really worked to get details right. There's no lake on Mt Rushmore, but the insides of the Library of Congress look right.
I can't see getting it on DVD but it was fun to watch.
A little side note. In a movie about finding messages hidden in strange places I saw one of my own. The President has Cage look on page 47 of the President's Secret Book.
There was a paper written in 1964 at Pomona College that claimed that 47 is the most common random number (or all numbers are equal to 47 depending on the source). It's been a long running joke there. If you know where to look the number 47 appears in some form in most episodes of Star Trek, as well as lots of movies, video games, music, and some of my passwords.