Dinosaurs Before Dark

Fantasy (fiction), Trade Book, Lexile 240

In this first installment of the Magic Tree House series, siblings Jack and Annie stumble upon a magic tree house full of books. They accidentally discover that the tree house is actually a time machine, only requiring that the inhabitants wish on a picture in a book to travel back in time. When Jack wishes on a dinosaur book that he could see a Pteranodon for real, the two are sent back to the Cretaceous Period. But dodging dangerous dinosaurs is just one problem. How on earth are they going to get back home to Frog Creek before their parents realize they are gone?