Due to an innovation of the American Museum of Natural History to attend people, 90% of its exhibits will be moved to the Federal Archives at the Smithsonian Institution in Washington, D.C. The moving ones are supposed to never come to life again since the Golden Tablet of Akhmenrah that animated the exhibits each night will also remain, but Dexter steals the tablet and that Akhmenrah's evil older brother Pharaoh Kahmunrah is attacking other exhibits. Larry Daley, who always considers these exhibits his friend, decides to go to Washington to save them.