It is the year 1600. a young man, Shinmen Takezo, from the village of Miyamoto in Yoshino district, signed up to fight in the Battle of Sekigahara. He was but a lowly foot soldier with an aspiration of making a name for himself. Together with his childhood friend, Honiden Matahachi, he joined the Army of the West. However, in a battle involving over 180,000 men, it was difficult to tell who was friend and who was foe. Amidst the confusion, Takezo captivated by the beautiful swordplay of a lone soldier from the Army of the East. That man's name was Sasaki Kojiro, a man that Takezo deemed as worthy of being his lifelong rival.

After the Army of the West suffered a crushing defeat in the Battle of Sekigahara, Takezo and Motohachi broke free from jail to hurry back to Miyamoto village so that they could reassure Motohachi's mother, Osugi, of their survival. Motohachi is engaged to Otsu, yet enroute to home, he was so bewitched by a voluptuous woman named Oko and her daughter, Akemi, that he ran away with them instead if heading home. While in pursuit, Takezo chanced upon Otsu and had rescued her. Unfortunately, while running away from their pursuers, Otsu had fallen into the river and fell sick. To save her, Takezo decided to head to Himeji Castle to seek help. Once there, he was promptly jailed.

After 4 years of incarceration, Takezo was freed and the lord of the castle, Ikeda Terumasa, together with Takuan, gave him a new name, Miyamoto Musashi, as he embarked on a journey to improve his sword skills.