Two decades ago, a catastrophic event shatters Pluto, redirecting the destructive asteroid Thanatos towards Earth. To avert this cataclysm, the ISDA initiates the ambitious 'D-Project', birthing the formidable 'Dragonaut' from a hidden dragon egg submerged under the sea. Tasked with obliterating Thanatos, the Dragonaut's purpose is clear. Yet, unforeseen dangers emerge as malevolent dragon-like beings descend upon Earth, heralding chaos. Drawn into this turmoil is Jin Kamishina, an isolated 18-year-old haunted by familial loss and a tragic shuttle incident. Witnessing a chilling murder by one of these creatures, Jin is thrust into the enigmatic world of dragons, chosen as the Dragonaut's pilot. Guiding him is Toa, a enigmatic girl who rescues him from peril during an attack. Together, they unravel the dragon mysteries, forging new alliances, facing adversaries, and nurturing a profound bond amidst the looming threats.