|One Saturday about 200 days before the national scholastic achievement examination for college entrance, there is a special elite class for only the school's top 20 model students. Now the only people there - I-na who is a righteous-minded high school girl; Gang-hyeon who is the school king but a rebellious boy; Hye-yeong, who is a paranoid holding steadfast to the top ranking in the school; Jo-beom who is a schizophrenic suffering from hallucinations and delusions, I-na's closest friend Myeong-hyo who is nervously jealous of I-na, Dong-hyeok, the school's second ranking student,who is suffering from insomnia; Jae-wook, the third highest ranking student, is very timid, and Joo-jin, the fourth ranking student who suffers from neurosis; Chang-wook, who is the most popular teacher in the school; So-yeong, the new teacher in charge of this elite class; and Chi-yeong who is the student dean. But during the class, the melody of 'Fur Elise' is suddenly played on the classroom TV and the School speaker, and the screen is showing the picture of Hye-yeong floundering in agony in a tank where water is gradually rising. And a voice is giving them a mid-term examination at the risk of Hye-yeong's life. It is impossible to escape this scene. There are only 24 people in the school. This is how the Death Bell mid-term examination began only for us.