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