Something is weird at the Museum of Natural History. There are hominids in the dinosaur exxhibit! Wilson Kipper knows this can't be right, since no hominids lived during the time of the dinosaurs, and it turns out his suspicions are correct: someone is altering the exhibit at night. Is someone on the janitorial staff? A new professor or her daughter? Or someone else? Wilson and his friends need to get to the bottom of this messed-up exhibit.