While delivering a bento to her husband's workplace, married woman Kaori accidentally loses her house key. Her husband's boss finds it, assigns her husband overtime, and sneaks into their home. He restrains Kaori while she naps, performs depraved acts on her, then uses photos to blackmail her upon waking. With a cruel, predatory gaze, the boss continues his assault. He increases her husband's workload, ensuring he stays late, while relentlessly raping Kaori during his absence. His desires spiral out of control, and the violence he inflicts on Kaori grows increasingly brutal each day.