On a visit to the Natural History Museum, Chase and Ava seem on the verge of finding out something important about the mysterious Randall, the missing scientist Finn, and the woman who gave them the suitcase filled with magical objects, when the dinosaur egg from the suitcase (they thought it was a potato) sends them back to dinosaur times--where they have to return the egg to the correct brontosaurus nest, while eluding hungry dinosaurs, and Randall, who it turns out is working for somebody called The Collector.