When her nephew is abducted, Kotomi is resolute in assisting her sister and brother-in-law. Defying the kidnapper’s instructions, she contacts the authorities. Detective Keisuke, leading the investigation, sets up a sting operation at the ransom exchange site, but the kidnapper never appears, and the boy remains missing. Fast forward two years, Kotomi weds a man named Makoto. Her sister and brother-in-law visit to celebrate the joyous event. That evening, the sisters, who had drifted apart since the kidnapping, share a room. Kotomi is startled awake by an alarm clock, only to discover she is in a dilapidated, abandoned factory, dressed only in her underwear and bound. Her sister is similarly restrained beside her. A man wearing a menacing mask stands before them, and a twisted ordeal begins as he repeatedly assaults the sisters.