Riona visits her uncle's house in her school uniform. Deeply interested in sex, she masturbates every day and is unable to concentrate on her studies. "I'm a naughty girl. I need to be punished..." A childhood memory comes back to her. My uncle used to scold me back then. He's the only one who can punish me... and so begins her masochistic training. Her immature body is tied up and her uncle thrusts his dick into her innocent pussy. The pain and shame turn to pleasure and she awakens to her masochistic tendencies...