After her husband is transferred for work and left to live alone, Kotoko Tokiwa finds herself sexually frustrated. Her desire is noticed by her brother-in-law, who begins secretly watching her masturbate. He then forcefully initiates a physical relationship, making Kotoko his prey. The situation escalates when he brings in a friend, subjecting her to a threesome and treating her like a toy. Gradually, Kotoko is completely dominated and consumed by her brother-in-law's control.