Yoshikazu is carrying his mother's luggage while on a family trip with his aunt Marina. She shows off her voluptuous body, just like she did back then, and he finds himself in a state of arousal. That night, having seen his aunt and uncle having sex, Yoshikazu is unable to sleep due to excitement and goes into the bath by himself... Marina comes in to wash off the sweat and sees his erect penis. Having been taught the joys of sex by her, Yoshikazu is not satisfied with the pleasure of it just once, and ejaculates inside her vagina again and again. Marina, who has not been satisfied with her husband, loses herself in his reckless thrusts and responds enthusiastically...