When Robbie fails to get a special birthday present, he makes a far-fetched wish on a falling star, waking to find he is a newborn Apatosaur. Confused and afraid, he must learn to adapt to his new surroundings in order to survive. As Robbie's plan unfolds for the final standoff with the ferocious T-rex, Tyra, he must decide if he is willing to risk losing his life for the sake of his friends.