While Ben is presenting new information about John Wilkes Booth and the 18 pages missing from Booth's diary, one man stands up and presents a missing page of John Wilkes Booth's diary. Thomas Gates, Ben's great-grandfather, is mentioned in the page. It shows that Ben's great-grandfather could have been a person involved with Abraham Lincoln's murder. When doing more research, the conspiracy takes Ben, Abigail, and Riley to Buckingham Palace(which they break into). It takes them to a book in the White House(which they break into also)and they even steal a page from the book. But in order to see more from the book, their choice is either get elected president or kidnap the President of the United States. Which do they choose? It's obvious. The conspiracy then crosses to Mount Rushmore and they even mention the JFK conspiracy. Could Ben clear his family's name? Or will his family be known as the descendant of Abraham Lincoln's murderer?

Here's the link:
http://www.vizda.tv/movie/120-National_Treasure_Book_of_Secrets_2007.html