Vol 1 - Kohaku discovers a strange ninja school and decides to enroll there "just out of curiosity". She immediately knew something was wrong when a man's dick was right in front of her. As he explained to Kohaku, it was part of the interview and her future would depend on how she sucked him off. Well, of course Kohaku is not used to this kind of test and she passes it with flying colors. Now she is greeted by Kunoichi, who will put Kohaku through a series of tests on her sexual stamina... Vol 2 - Kohaku and Kunoichi continue their lecherous tests. This time the girls have to do some sex training at a waterfall near the hot springs - trying out some dildos and trying out some lesbian sex techniques. Next, Kohaku goes to the lab to investigate a brand new technologically advanced sex machine in the form of a regular chair. After a long and thorough research, the heroine was unable to discover its practical potential; she needed an outside view. For a more detailed and qualitative research, Kohaku invited Kunoichi as an assistant and a test subject...