The younger sister, aroused by her older sister's moans while in bed with her bunk bed, is a 5-year-old summer vacation girl. (SP NHDTA-277)

The fifth installment of the popular series, a summer special. Two sisters from the same high school badminton club are assaulted by their dormitory staff and their father's subordinates who are also there for training… The older sister, who is forced first, tries desperately to keep her voice down so her younger sister won't hear, but an unintentional moan arouses the younger sister, giving the assaulting man a delicious "sister donburi" (a euphemism for sexual intercourse between sisters)!