The vigorous sexual desire 21-year-old Seung-ah is more than 10 years old. She is not satisfied with her husband's sexual life. So I'm secretly enjoying affair with other men. I even had sex with my younger brother Dong-jun once. Meanwhile, Dong-jun suffers from guilt after having sex with her younger brother, Seung-ah, but she cannot forget her sex with Seung-ah. Dong-jun starts to meet ex-girlfriend who broke up to remove Seung-ah from her head.