Trapped in an affair, married woman "Nanami" finds her love for her husband fading, growing weary of daily life. When a young man moves into her apartment building, his kindness and warmth stir emotions she thought long gone, awakening her suppressed desires. Overcome by loneliness and dissatisfaction, Nanami seduces the younger man, drawing them into a forbidden relationship. But her feelings go beyond mere infatuation—driven by intense sexual cravings, she begins monitoring him, imposing restrictions, and asserting control. Her actions grow increasingly obsessive, pushing their illicit affair into dangerous, cruel territory.