While Benjamin Gates (Nicolas Cage) is presenting new information about John Wilkes Booth and the eighteen pages missing from Booth's diary, a man by the name of Mitch Wilkinson (Ed Harris) stands up and presents a missing page of John Wilkes Booth's diary. Thomas Gates, Ben's great-grandfather, is mentioned on the page. It shows that Ben's great-grandfather was a co-conspirator in Abraham Lincoln's murder. When doing more research, the conspiracy takes Ben, Abigail Chase (Diane Kruger), and Riley Poole (Justin Bartha) to Buckingham Palace (into which they break). They discover a plank that has early Native American writing on it. The plank has only one symbol that Patrick Gates (Jon Voight) can identify. The symbol is Cibola (see-bowl-uh), meaning the City of Gold. In order to define the rest they have to go to Ben's mother, Patrick's divorced wife, Emily Appleton (Dame Helen Mirren). After thirty-two years, it brings back old arguments. After that, the other clue is in the President's desk in the Oval Office in the White House (into which Ben and Abigail sneak) to discover that the clue lies in the President's Book. But in order to see the book, their choice is either get elected President or kidnap the President of the United States (Bruce Greenwood). Which do they choose? It's obvious. With Wilkinson close on their tail, they find the book in the Library of Congress. The conspiracy then crosses to Mount Rushmore where the clue was in the hills, but (according to the Book) President Calvin Coolidge had the faces carved in so no one can find the City of Gold. When they get there, they find out that they must work with Wilkinson since he has some clues of his own. Who will claim Cibola? And will the name of Gates be known as murder?Benjamin Gates (Nicolas Cage) must follow a clue left in John Wilkes Booth's diary to prove his ancestor's innocence in the assassination of Abraham Lincoln.