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.

Cast: Uhm Ki-joon, Kim So-hyun, Lee Min-hyuk, Seo Shin-ae, Baek Seung-do, Kim Ji-ahn