A homeroom teacher of Yosan Private High School has an accident, and thus a substitute comes to fill in. Han Bong-Gu is a mysterious man, and after strange occurrences the class president Ye-Rim tries to get to the bottom of this mystery.

• Uhm Ki-joon
• Kim So-hyun
• Lee Min-hyuk
• Seo Shin-ae
• Baek Seung-do
• Kim Ji-ahn
• Jang Kyoung-up
• Kim Da-ye