The Pteranodon family rides the Dinosaur Train - now with extra cars attached -- as it continues picking up more dinosaurs that are in the 'Dinosaurs A to Z' song. The Pteranodon family reunites with some dinosaurs they've met before, and are introduced to species they've never met. The Pteranodon kids also learn about classification, and Don leads the way organizing the dinosaurs on the Train by their species, features, and size.