Remarried to an emotionally distant husband who treats her stepson coldly, Saho harbors deep sexual frustration and repeatedly cheats with an insurance salesman. One day, her stepson sneaks into her room and discovers video footage of her affair. Using the evidence to blackmail her, he forces himself on her, raping her against her will. Falling into the role of a sex slave, Saho is reduced to a mere toy, used by her husband and stepson in every possible way—even in places her husband cannot see. An endless cycle of humiliation and degradation slowly consumes her mind.