During a civil war, the nation of Zipangu is inhabited by people who coexist with gimmick warriors, superhuman robots. In this turbulent setting, both humans and gimmick warriors vie for dominance. Musashi, a Samurai gimmick warrior, sets out on a quest to become the finest Samurai warrior. He proves himself in a succession of battles, confronting numerous heroes and villains, including his lifelong rival Kojiro, a master swordsman. Later, the General assigns Musashi and Kojiro to escort the General’s granddaughter, a spoiled and difficult princess, turning their journey into a series of misadventures that soon draws them into a clash for control of the country.