One day, just as he was starting to think about getting married to his girlfriend, his girlfriend's younger sister, Ria, came to stay the night. Although she was a little airheaded, Ria was a very innocent and beautiful girl, nothing like his girlfriend. She was also weak to pressure and very sensitive, so she could do whatever she wanted! When he was having sex with her secretly without her knowing, her erotic side was awakened and she started asking for sex every day and he kept having sex with her!