Hideki's a decent guy overall and realises it's a bit perverted to have his girl persocom running around the place with no underwear. Unfortunately, inexperienced as Hideki is, buying female undergarments holds a great source of embarrassment for him. Hearing about the dilemma Shinbo offers Sumomo's services as navigator and generally being a source of common sense for Chii, in order for her to go and buy her own underwear. This sounds like a great idea at the time, but causes a seemingly infinite amount of worry during the day at prep school for Hideki.

Hideki is scared of a room in the apartment because of a horror story he heard at Minoru's house when he was asking about the internet through Minoru's custom-made Persocom Yuzuki. He becomes paranoid thinking about the story and, believing that his apartment building is haunted, has several self-induced hallucinations. The apartment number in the story is 104, as 4, or shi. "Shi" is the Japanese word for Four (四) and Death (死), and because of this, the number four is unlucky in Japan. According to the story, a woman who was hoping to rendezvous with her lover was killed in that room. Hideki and Chii along with Shinbo, Minoru and Yuzuki decide to investigate. At the end, Hideki and Chii discover that it is all a misunderstanding.