Pete (Oakes Fegley) is a 10-year-old boy who has been living in the woods for years. He hasn't been around humans, instead living a peaceful life with Elliot, the dragon who found him when he was four, and the other animals of the forest.
When a forest ranger (Bryce Dallas Howard) spots Pete, she tries to figure out where he came from. Worried for his safety, she takes him in. When he draws a picture of Elliot and claims the dragon is real, she goes to her father (Robert Redford) for advice. For years, he's been telling local kids about meeting a dragon living deep within the forest. Grace tries to get to the bottom of Pete's unbelievable story and his mysterious friend.