Two planets, one to the East and another to the West, were once bound together by a chain called the Dragon Stream. But now, that chain is broken and the two halves are only joined in war. Nobunaga the Fool is heir to the Eastern Country of Owari. Regarded as too foolish and carefree by many, including his friends, Nobunaga is thought to be a nuisance even by his father. A girl from the West named Jeanne Kaguya d'Arc has visions of a "Savior-King." She is accompanied by Leonardo da Vinci as she journeys to the Eastern Planet in search of the person in her visions. Leonardo and Jeanne quickly fall victim to a military confrontation between powerful mecha, only to be saved by Nobunaga. Nobunaga takes control of Leonardo's mecha, intending to warn his family of the siege he suspects. Jeanne suspects that the lackadaisical Nobunaga might be the Savior-King she's envisioned.The Western Planet and the Eastern Planet. Once upon a time, the two sides were bound by the “Dragon Pulse” spanning the heavens. The civilization that once had prospered has now turned to a tale of dreams, as the inextinguishable flames of war tear the realm asunder. The two planets remain engulfed in endless battles. The return of the super technology known as “sacred treasures” could revolutionize the world order, but no one knows of them but one person—a “heretical girl.” A girl from the Western Planet, Jeanne Kaguya d’Arc, saw heavenly visions of the birth of a “Star Messiah” who will save the world. She embarks on a journey to the Eastern Planet with Leonardo da Vinci, “the one who observes the world.” They come across the heretic of the Eastern Planet and “the greatest fool of the day,” Oda Nobunaga.