Deep in a tropical jungle, young Yaiba Kurogane diligently practices swordsmanship alongside his father, Kenjuurou, completely unaware of the modern world. However, one day, the two end up in a container on its way to Japan. There, they encounter Kenjuurou's old rival, Raizou Mine, and his daughter, Sayaka. Out of other options, Yaiba agrees to a deal with the Mine household: if he beats the strongest student in thei...