Uiba Shikatani's father, who owns a pet shop, is saddened by his daughter's disappointment when some of her reptile eggs failed to hatch. In an effort to cheer her up, he brings home a large, striped egg that he hopes will successfully hatch into a green dinosaur named "Muka-Muka," the only words which the baby reptile can speak. The town soon becomes fascinated with Muka-Muka and he gains attention from the local professor and his wacky inventions, including a time machine that transports the Shikatanis and other families to prehistoric times where they encounter various dinosaurs and magical beings on their adventures.