the earth", but points out that some of the glyphs are partial. Ben and Abigail convince Abigail's new boyfriend Connor, a White House Curator, to let them see the Resolute Desk in the Oval Office. Ben discovers that the second plank has been replaced by a stamp of an altered Presidential seal, which Riley identifies as the symbol for a secret shared diary, written by Presidents and containing controversial topics such as Watergate, Area 51, and the JFK assassination. Ben's FBI friend Agent Peter Sadusky confirms the book's existence, but warns that no one can read its contents without express permission from the sitting President. Ben crashes the President's birthday party at Mount Vernon to convince the President to explore a secret tunnel with him. There, Ben activates a secret sliding door, separates the President from his guards, and asks him about the book, while safely leading the President to freedom at the other end of the tunnel. The President sympathetically warns Ben that his actions, while innocently meant, will be interpreted as attempted kidnapping. He then reveals the book is hidden in a safe at the Library of Congress, asking Ben to find out what is on page 47 for him. Pursued by the FBI, Ben, Abigail, and Riley manage a brief look at the book. They find a photograph of the missing plank, and an entry by Calvin Coolidge. He found the plank in 1924, translated it, had it destroyed, and commissioned Gutzon Borglum to carve Mount Rushmore, to hide evidence of a hidden treasure nearby. After consulting Emily about the glyphs, Ben, Riley, Abigail, and Patrick head to Mount Rushmore. They meet Mitch and Emily there, as Mitch kidnapped her after Ben left. Mitch already has acquired, memorized, and destroyed the final clue, so he can claim the treasure. He helps the group find the entrance of a cave full of booby traps. After briefly getting separated, the group finds a pit containing Cíbola, a Native American city of gold. An ancient dam fails, and it becomes clear one of the group must sacrifice themselves in the quickly flooding cave to hold open the door for the others. Mitch does so, but begs Ben to give him posthumous credit for finding the treasure so he can be in the history books, too. Ben and the rest return to the surface, where the President prevents Ben from being