As the students of Year 3 class C at Keyaki Academy Private School arrive in the morning, they find the remains of their homeroom teacher, Tokuyama Daigorou, who killed by a knife stabbed into his back. The students panic and decide to hide his corpse. A strange school life begins as the students work hard to hide the presence of their teacher's corpse in their classroom. Other teachers, their homeroom teacher's wife, his mistress, police, and reporters... One-by-one they visit the classroom and the students face the risk of being discovered.