The third term has begun, and a new homeroom teacher has been appointed to class 5 and 3 at Takehaya Elementary School. His name is Toshihiko Ochiai. When Hiroshi and his five friends saw his face, they were shocked. It turns out that Ochiai is the suspicious man who was following Hiroshi's activities and taking notes yesterday. However, it was also true that Ochiai had a mysterious charm that set him apart from other teachers.