Marina remarried to the owner of a small company, but lacking affection for her husband, she found herself unfulfilled in daily life. She soon fell into an affair with a male coworker. Her stepson, Yusaku, discovered the infidelity and secretly photographed her, using the evidence to blackmail and assault her. From then on, whenever Yusaku visited the office, he implanted a vibrator inside Marina, forcing her to suppress her moans as she was pleasured against her will. One by one, Yusaku's friends took turns raping her, gradually breaking her down and turning her into a submissive sex slave. Through this process, Marina is forced to confront where she truly belongs and whom she should depend on.