Jiyu "Jubei" Nanohana and her ineffectual father recently moved to the country from Tokyo, so she's a new student at Hontsuru Junior High. She immediately wins the hearts of the proudly "unrefined" Bantaro and the elegant kendo champion, Shiro. Every male she encounters takes one look at her breasts and is instantly smitten. Although she's unaware of it, Jubei is the reincarnation of master swordsman Yagyu Jubei. His loyal retainer Koinusuke has spent the last 300 years looking for the person destined to inherit the "lovely eye patch" that transforms the wearer into an unbeatable warrior. In addition to Yagyu's soul, Jubei has inherited a 300-year-old vendetta: the Ryujoji clan wants to eliminate her so they can rule Japan by the sword!