主水之助七番勝負 徳川風雲録外伝

During the reign of the 8th Shogun Tokugawa Yoshimune, Mondonosuke, a young retired Jikisan-Hatamoto learns from Yoshimune who saved him from a crisis on his samurai training trip about the assassination of Iwashiro Yasutaka, the lord of the Kameda domain. Mondonosuke realizes that Omine-no-Zenki who was his apprentice brother is responsible for the assassination. Zenki was supposed to have been put to death five years ago. In order to defeat Zenki who is now on the loose... Mondonosuke must battle through a series of fights.