Erin is a 10-year-old girl living with her mother in the Tai Koh Region. She has a deep affection for animals, particularly the Touda, dragon-like creatures utilized in warfare. Her mother, Soyon, originally belonged to the Mist People, an ancient clan characterized by green eyes. Because Erin's deceased father was the son of the chief of a village of Touda breeders, Erin and Soyon reside there, and Soyon serves as the head Touda doctor. However, one night, the Kiba, the Duke's most powerful Touda, die under mysterious circumstances, and Erin's life will be changed forever, drawing her into the fate of the entire country. The series chronicles Erin's life from childhood through adulthood.