Rena's daughter has gotten married and two generations live together. The family is on good terms and outwardly they seem to be living happily, but... she is not satisfied with her relationship with her husband and secretly consoles herself. One night, her son-in-law Satoru is secretly watching them... When he hears the story, he learns that his daughter rejects him because his penis is too big. Captivated by his stiff penis, Rena tells him that it is for the sake of reconciling the daughter and son-in-law, and provides sexual relief for him... Satoru is confused by the sudden turn of events. However, he is soon captivated by his mother-in-law's seductive techniques, who are constantly coming at him...