Larry Daley (Ben Stiller), a down-on-his-luck dreamer, takes a job as a night watchman at the Museum of Natural History. However, he soon discovers a magical secret: the exhibits come to life after sundown! Larry finds himself caught in the middle of hilarious chaos as historical figures like Teddy Roosevelt (Robin Williams), Sacagawea, and Attila the Hun, along with dinosaur skeletons and lions, wreak havoc in the museum. He must learn to navigate the mayhem and become an unlikely hero.