Death Bell 2008

As the countdown for college entrance exams begin, Chang Ahn High School organises a special exam cram class for the top 20 students including girl-next-door Lee Na (Nam Gyu Ri) and classroom big shot Hyun Kang (Kim Bum). Taught by Hwang Chang Wook (Lee Bum Soo) and three other teachers, the class is festering with high-strung over-achieving teens, some of whom are struggling with serious mental illnesses. In the middle of class, the television suddenly turns on. The students are shocked to see their classmate Hye Young drowning in a water tank onscreen. A voice asks them a sample exam question...