Mr. Chummu (Robert Redford) is an old carpenter who always likes to tell children a story about a dragon. The dragon in the story lives in the dense jungle in the Pacific Northwest. Mr. Chummu says he has witnessed the existence of a dragon with his own eyes. His daughter Grace (Bryce Dallas Howard) is dismissive of this story that her father has told a million times. She thinks it is definitely a story that her father made up. By chance, Grace met a boy named Peter (Oakes Fegley). The boy told Grace that he had no relatives or home, and his only friend was a flying dragon named Elliot. Pete's narration reminded Grace of her father's story, which was surprisingly similar. In order to confirm Peter's words, Grace embarked on a journey to find a dragon.