"Sperm donation" refers to a method where couples struggling with fertility receive sperm from a general male donor to achieve pregnancy. This time, a couple in their second year of marriage appears. Wife Yui says, "Due to our age difference, fertility efforts have been quite difficult," as her older husband quietly nods in agreement. Bound by an age-gap marriage and unable to conceive, the couple begins exploring sperm donation as an option. Later, to prepare for timed intercourse—a method with higher pregnancy rates—Yui undergoes preparatory massage. Stimulated by the treatment, her sexually frustrated body becomes aroused, and she eventually succumbs to the temptation of sex with a younger man, losing herself completely in the pleasure.