Emi (Ai Saka Haruna) had been happily married to her husband Koichi for three years, enjoying a peaceful family life. However, one day, her husband's company proposed a transfer to company housing, leaving Emi home alone more often while Koichi was away. During this time, she accidentally discovered a hidden secret staircase leading to the upstairs apartment, where her husband's boss, Tayashiro, lived. When Emi stepped into the concealed room, Tayashiro caught her and, using threats, forcibly raped her. After that, Tayashiro's sexual demands escalated, gradually trapping Emi in a situation from which she could not escape. She lost all control over her own actions, completely consumed by a whirlpool of carnal desire...