In the office where Natsume works, the walls of the conference room have been replaced with one-way mirrors. This is apparently to eliminate the feeling of claustrophobia and create an open, comfortable working environment. "You can't see inside from the outside, but you can see outside from the inside..." Natsume's heart races in this unrealistic space, and he ends up satisfying his frustrations in the conference room in the middle of the night. He doesn't realize that if it's dark outside the room, you can see inside...