40-year-old Sociology professor Hye-jung falls for a 21-year-old Usang, a male student who helps her project research on women's extramarital affair. Their prohibited love and secrets are watched and told by two secretive observers. They are her copy machine and his digital camera.

• Jang Seo-hee
• Jung Suk-won
• Lee Pil-mo
• Shim Yi-young
• Son Ji-na
• Park Hee-jin
• Wi Ji-Woong