Shintarou has a older sister, Minaki, she is gentle, smart, and pretty. She is the most popular girl at the school they both attend.
However, that is only the face Minaki shows at school, at home she enjoys teasing Shintarou a lot.
One day while Shintarou is watching a S&M Adult Video he received from a friend, he is caught by Minaki.
So you like this kind of thing Shintarou-chan, Onee-chan will make you feel good, says Minaki.
Shintarou learns firsthand that his beloved Onee-chan enjoys doing more than just teasing. She is a complete S.