Yui is a serious and healthy young wife of a small factory. She is coaxed into going out for drinks with her technical intern trainee by her factory manager's husband, who has discovered his habit of cuckolding her. The intern, who has not been able to release his sexual desire, can't control his horniness towards her wife, and begins to mess with her, which gradually escalates. Yui accepts it for the sake of her husband, but she gradually becomes unable to resist the pleasure of the big dick.
