A rental apartment building located a 7-minute walk from the station, constructed about 7 years ago—close to the city center yet offering a well-maintained living environment with furnished rooms and appliances. The property is managed by a popular management company, whose male employee possesses a master key kept under strict control. His true purpose: unauthorized entry into the apartments of female tenants. A woman in her mid-20s, dressed like a schoolteacher, returns home and immediately begins grading exams. Midway through, she feels the urge to urinate and heads to the bathroom. Afterward, she drinks a beverage to rehydrate—but it contains a secretly mixed-in aphrodisiac drug. Unaware, she quickly loses consciousness. As the man breaks into her room and begins molesting her unconscious body, she later awakens to discover unfamiliar objects inserted into her genitals, marking the beginning of a twisted encounter.