Riley Poole is a sarcastic computer expert, resident genius, and best friend of Benjamin Franklin Gates. He tries his hardest to be funny and smart, but doesn't always succeed. He can be nerdy most of the time and get annoyed when people don't listen to him. He loves it when he knows something Ben and Abigail don't!
He figured out the clue involving the one hundred dollar bill and Independence Hall. When he realizes that Abigail and Ben do not know what he knows, he takes his time, asking them if this is what they always feel like (much to their anger). Before that Riley tried to convince Ben that stealing the Declaration of Independence was impossible due to the security at the National Archives.
After the events of the previous movie, Riley enjoys life with his Ferrari. He is first shown in a bookstore, advertising his new book, The Templar Treasure, a book about treasure hunting and myths. He is shocked when it is not a bestseller and people keep confusing him for Ben. To make matters worse, the IRS repossesses Riley's car, and many of his belongings, because of back taxes.
Defeated, Riley reunites with Benjamin Gates. Both he and Ben discuss recent problems in their lives. Ben convinces Riley to join him for another treasure hunt to the City of Gold, to prove Thomas Gates was not part of the plot to kill Abraham Lincoln.
However, the alleged note proving Thomas Gates aided the assassination of Abraham Lincoln is kept in Abigail Chase's house. Because Abigail broke up with Ben and kicked him out, both he and Riley need to break into her house to access the note.
During their break-in, Abigail catches them trying to steal the page. However, she allows them access to the files they need. Using spectral imaging, they discover a cipher by Edouard Laboulaye, the developer of the Statue of Liberty. The cipher leads Ben and Riley to the French Statue of Liberty in Paris, France.
In France, Riley and Ben discover a French inscription on the statue's torch by using a drone. With the help of two French police officers, Ben and Riley translate the text, which leads them to the Resolute Desks. Riley, again, is frustrated, because the police officers recognize Ben, and not him. The officers also ticket Riley for flying a drone around the Statue of Liberty.
To access the first of the Resolute Desks, they must enter the Buckingham Palace in London. By using his technological prowess, Riley helps Ben, and later Abigail, to access the Queen of England's office. Together, they find a plank of wood with an ancient Native American language engraved on top. However, before they can study it, the three treasure-hunters are ambushed by Ben's arch enemy, Mitch Wilkinson. To escape being captured by Mitch and his team, Ben takes a photo of the plank, and throws it into a river. Mitch abandons his pursuit of Riley, Ben, and Abigail, and obtains the plank.
Later on, Ben and Abigail access the Resolute Desk in the Oval Office. However, they realize that the ancient plank had been destroyed, and the only surviving photo resides in a hidden area. Riley quickly figures out where the photo is located, because of the research he conducted while writing his book. Upset after he realizes that none of his friends had read his book yet, Riley tells the rest of the team that the photo resides in the President's Book of Secrets. Together, Riley, Ben, and Abigail begin discussing how they will retrieve the heavily guarded book, and reluctantly agree that they must kidnap the President.
Deciding that they should kidnap the President during his birthday party, Riley uses his tech skills to force the president to book his party at Mount Vernon, where Ben could easily sneak in and kidnap him.
Ben quickly obtains the information to locate the Book of Secrets, and the three treasure-hunters rush to the Library of Congress where the book is kept. After reading information written by President Calvin Coolidge, the trio realizes that the City of Gold is located behind Mount Rushmore (which to Riley's surprise was built as a cover up).
At Mount Rushmore, Riley, Ben, and Abigail meet Wilkinson, and Ben's parents. They agree to search for the treasure together. Despite many booby traps, and disagreements between Wilkinson and everyone else, all six of them reach the City of Gold. During their discovery of the city, Riley takes several gold bars. However, upon their escape, the team of treasure-hunters are trapped in a flooding room with a door that can only remain open if one person stays behind. Wilkinson, satisfied that he found the City of Gold, stays behind and sacrifices himself for everyone else.
Riley, now rich again, is back at the bookstore, where an attractive woman finally recognizes him as a famous treasure-hunter. Riley is last seen walking down the street, where he recognizes his Ferrari. On the car is a letter from the president, which reads, "tax free." Excited to drive his car again, Riley pushes on the gas, reverses, and consequently crashes.