The story takes place in medieval Japan. Tanaka Nanaka (voiced by Yoshimasa Hosoya) is a man with a strong appearance and a simple mind. Born into a martial arts family, he shoulders the heavy responsibility of inheriting the "Hypokalyu". From childhood to adulthood, Tanaka Nanaka has been trained as a sword. This perverted way of education has led him to the tragic path of parricide. Under the instigation and instigation of the strange strategist Gui'er (voiced by Yukari Tamura), Tanaka Nanaka embarked on a long journey of practice. He wanted to find the 12 famous swords forged by the blacksmith Shikisaki Kiki (voiced by Koji Mori) to enhance his strength. Along the way, Tanaka Nanaka encountered all kinds of enemies, and he had no choice but to kill them one by one. However, when his relatives and friends died one after another, the dull Tanaka Nanaka began to think about the value and meaning of being a sword.