In a world where dinosaurs and humans live side-by-side, an Apatosaurus named Arlo makes an unlikely human friend.

Luckily for young Arlo, his parents (Jeffrey Wright, Frances McDormand) and his two siblings, the mighty dinosaurs were not wiped out 65 million years ago. When a rainstorm washes poor Arlo (Raymond Ochoa) downriver, he ends up bruised, battered and miles away from home. Good fortune shines on the frightened dino when he meets Spot (Jack Bright), a Neanderthal boy who offers his help and friendship. Together, the unlikely duo embark on an epic adventure to reunite Arlo with his beloved family.