Kurogane Yaiba, a boy with a unique ambition to become a samurai, trains rigorously with his father in the forest. His journey takes a turn when he is suddenly thrust into the unfamiliar world of Japan. There, he crosses paths with the Mine family, the malevolent Onimaru, and the renowned Musashi, embarking on perilous escapades that test his strength and character, pushing him to grow stronger with each passing day.