Half a year has passed since they got married. Kasumi and her husband still feel like newlyweds, but when Kasumi's stepchild Fumiya comes home from a trip to Japan, her mother-in-law Reiko feels a little awkward. One day, Fumiya collapses from dehydration while taking a bath. Reiko rushes to his aid, but she can't take her eyes off his magnificent penis... Reiko begins to stroke it with her hand, and when Fumiya notices, she is begged to help him ejaculate. However, Fumiya is not satisfied and shows off his youthful, rock-hard penis to Reiko again...