Jiyu Nanohana is an ordinary schoolgirl at Hontsuru Junior High, until she stumbles upon a mysterious item. Unaware of it, Jiyu is the reincarnation of a master swordsman named Yagyu Jubei. His loyal servant, 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. When she puts it on, Jiyu transforms into Jubei II. In addition to inheriting Jubei’s power and skills, Jiyu as also inherited a similar rival. The Ryujoji clan wants to eliminate her so they can rule Japan by their sword.

“Jubei-chan - Secret of the Lovely Eyepatch” or “Jubei-chan - Lovely Gantai no Himitsu” is the first installment in the series. It is followed by “Jubei-Chan 2: The Counter Attack of Siberia Yagyu”