In a time of drought, several herds of dinosaurs seek an oasis known as the Great Valley. Among these, a diminished “Longneck” herd gives birth to a single baby, named Littlefoot. Years later, Littlefoot plays with Cera, a “Three-horn”, until her father intervenes; whereupon Littlefoot’s mother describes the different kinds of dinosaurs: “Three-horns”, “Spiketails”, “Swimmers”, and “Flyers”. That night, as Littlefoot follows a “Hopper”, he encounters Cera again, and they play together briefly until a large brown “Sharptooth” attacks.