Ronnie is just a normal fifth-grader trying to pass her science class's impossible quiz on the history of dinosaurs . . . until she runs into her neighbor-Ms. Lernin-a retired paleontologist. Ronnie and Ms. Lernin travel back through time to experience the age of the dinosaurs firsthand. They visit three important time periods of the Mesozoic Era: the Triassic, the Jurassic, and the Cretaceous. Along the way, Ronnie finds herself face-to-face with real-life dinosaurs and reptiles, like Stegosauruses, Velociraptors, and Thalattosaurs. She learns the differences between herbivores, carnivores, and omnivores, as well as between dinosaurs, insects, and reptiles.