Hiroyuki received a sudden visit from his sister-in-law, Yui. She thought that her daughter-in-law would go on a two-day trip with her friend, and she would be able to enjoy herself alone for the first time in a long time. Hiroyuki was surprised at her, but Yui took over all of her housework and completely bonded with her. She has no way of knowing that Yui's real purpose is to release her libido. Yui sees Hiroyuki go to her bath with a bewitching smile, and she begins to take off her clothes.
