Starting out in Edo, as Kyoshiro travels west toward Kyoto, he encounters some of the most dangerous obstacles in his career. Signs that the Tokugawa shogunate was vulnerable began to appear during the reign of 12th Shogun Ieyoshi. The Satsuma and the 13 Western non-Tokugawa lords began to act in suspicious ways. Minister Takebe, under orders from shogunate councilor Mizuno, attempted to quash this unrest. Nemuri Kyoshiro, a loner headed west, unwittingly becomes involved in the struggle.

The story chronicles the life of Yagyū Munenori.

Saotome Mondonosuke, "Hatamoto" (direct servant of the shogun), a handsome man with a scar on his forehead in the form of a crescent moon, a favorite of the shogun. He is a master of martial arts, who owns the style of Moroha-ryu seigan-kuzushi (fencing), Yoshin-ryu tai-jutsu (the art of fighting without weapons) and even military science, but in the era of Genroku (1688-1704) all these skills are not in demand, and this brings boredom to Mondonosuke. To dispel boredom, this so-called "bored gentleman" walks around the city, and when he hears about some incident, he rushes to the place and defeats evil with his invincible swordsmanship. Mondonosuke has a 17-year-old sister, Kikuji (Yukiko Kashiwagi), and Kikuji's lover, Kirishima Kyoya (Takao Kataoka), becomes his right hand.