Death Bell (Korean: 고死: 피의 중간고사; RR: Gosa: Piui Junggangosa) is a 2008 Korean horror slasher film. The only Korean horror film released over the summer of 2008, it is the first feature by former music video director Chang, who also co-wrote the screenplay. Death Bell stars Lee Beom-soo in his first horror film role, and K-pop singer Nam Gyu-ri in her acting debut. Set in a Korean high school, the film's native title refers to gosa, the important midterm exams that all students are required to sit. It is later followed by a stand-alone sequel Death Bell 2: Bloody Camp. Plot.
https://en.wikipedia.org/wiki/Death_Bell