An asteroid is headed for Earth, and to prevent the impending destruction, the ISDA creates the "Dragonaut" after discovering a dragon egg beneath the ocean. This weapon's main purpose is to destroy the asteroid when the time comes. However, they soon realize that the asteroid isn't their only threat, as powerful dragon-like creatures intent on destruction emerge. After witnessing a murder committed by one of these creatures, Jin Kamishina, a lonely 18-year-old boy who lost his family in a shuttle accident, becomes embroiled in the mysteries of the dragons and is chosen as the pilot of the Dragonaut. Assisting him on his journey is Toa, a mysterious girl who saves him from falling to his death after the creature attacks him.
