Babysaurus loves to play hide-and-seek in the jungle with his Papasaurus, but one day Papasaurus hides and Baby cannot find him--so he asks the other dinosaurs--Stego, Anky, Velo, and others--for help finding his father.
When Ms. Frizzle takes her class to a dinosaur dig to look for Maiasaura nests, the Magic School Bus turns into a time machine and transports them back into prehistoric times--when dinosaurs roamed the Earth.