After losing his wife, a sexually insatiable older father-in-law sets his sights on his son's wife, Maki. He deliberately shows her lewd photos to spark her interest, proudly flaunting his massive cock. In stark contrast to her husband's dull sex life, Maki becomes captivated by her father-in-law's intense sexual techniques and experienced rope bondage skills. Gradually, her feelings for him begin to grow stronger than those for her husband, until she realizes she has fallen in love with him. An unusual, forbidden emotion develops, transcending their familial roles. Maki's heart now aches, unable to forget her father-in-law's inexhaustible, rock-hard cock.