The 4th installment of 'Kasumi', direct-to-video erotic ninja action series based on the manga by Youji Kanbayashi & Jin Hirano. - Kasumi is a female ninja working for Sanada clan. While searching for the scroll which describes some secret about Osaka Castle, she is saved by Sakichi, another ninja from Sanada. He is actually an ex-ninja. He has quiited when he lost his sweetheart in the battle. Shortly afterwards, Kasumi is captured by Hattori clan. Sakichi is the only one who can save her from Hattori. When Sakichi learns Kasumi also lost her family in the battle, he is determined to return as a ninja. (Later, Sakichi is to become a great ninja under the name Sarutobi Sasuke.)
