Uiba Shikatani, the daughter of a pet shop owner, is heartbroken after several reptile eggs fail to hatch. In an effort to cheer her up, her father brings home a large, striped egg he hopes will successfully hatch. Unexpectedly, the egg hatches into a green dinosaur they name “Muka‑Muka,” whose only spoken words are the sound “muka‑muka.” The curious baby soon becomes the talk of the town and draws the attention of a local professor known for his eccentric inventions, including a time machine. The machine transports the Shikatani family, along with other families and their homes, to prehistoric times, where they encounter a variety of dinosaurs and enchanted beings on their adventures.