Married for five years and with no children... Hibiki, a married woman working part-time at a factory in the city, is called out to by Hajime, a young man who also works part-time at the same factory, on her way home from her part-time job. "Thank you for your hard work, Otsuki-san." There is an awkward atmosphere between this man and woman, who seem to be on friendly terms, yet somehow seem aloof and shy away from the public eye. A married woman and a university student. This is the record of her affair, in which her "Rina uterus" that cannot be satisfied by her kind husband is penetrated by his impressive, large young penis...