Sakuragi Mion HBAD-694 is troubled after being secretly sexually assaulted by her brother's girlfriend, who has a slender figure, a slim waist, and small breasts.

Aine is Mengshu's girlfriend, a slender beauty whom Aine has always secretly admired. One day, on her way to work, Aine realizes she forgot her phone and rushes home. At the apartment door, she sees Mengshu go inside. Her brother should be at work, but Aine is in the apartment. Aine sneaks into the bedroom and finds Mengshu licking an older man's penis…