After young apotosauras Arlo's father getting washed away by a flood. He blames a cave kid named Spot for killing him. Spot suddenly knocks Arlo into the river and Arlo gets washed away and gets lost in the woods. Arlo then later turns from scared to brave, and he becomes friends with Spot, and Arlo then meets a clan of T-Rexes who find Arlo's way home. Can Arlo be the bravest living dinosaur or will he sometimes still be afraid?