On their wedding anniversary, Yui was supposed to go on a hot spring trip with her husband Ryuichi and her father-in-law. However, due to Ryuichi's work delay, she ended up going with her father-in-law first. Although Yui felt somewhat awkward, as they toured the hot spring town and became more at ease, she proposed washing his back in the bath. Knowing that Yui was feeling lonely because of Ryuichi's cold attitude, her father-in-law accepted her kindness. Touched by her father-in-law's gentleness, Yui began to reveal her beautiful body in the bath…
