The students find something hidden in the air-conditioner. Was it their homeroom teacher, Daigoro Tokuyama who hid it? As the students investigate, Detective Yashiro suddenly returns. The next day, the classroom is hot, and the body is reeking. That's when Neru Nagahama suddenly comes back to school. They interrogate her the moment the teacher leaves the room.
One morning, students find their homeroom teacher Tokuyama Daigoro’s body on the floor of the classroom. A strange school life begins as the students work hard to hide the presence of their teacher's corpse in their classroom. Other teachers from the Academy, 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. Is it possible to continue to hide it?! And who was it who killed him?!
