Three days after graduation, Mio Kimishima is betrayed and gang-raped by her students at a party. (HND-533)

Ms. Kimishima Mio is invited by her students to a graduation party. Three days after the graduation ceremony, they gather at an izakaya (Japanese pub) near a student's home. However, this is actually a scheme orchestrated by a female student to get revenge on her for dating the male teacher she has a crush on, leading to the entire class assaulting her. What started as a graduation party turns into a gang rape party...