Sakura Shiratori, a female teacher, had just started to get used to teaching at an all-boys school. However, her routine life takes a dark turn when she becomes entangled in a horrific incident. She is caught in a gang rape by male students, forced to run naked as her pale skin and massive breasts tremble with fear. No matter how hard she tries to escape, she is found and repeatedly raped by numerous students. Even the fathers of some students end up violating her as well. Sakura is blackmailed by the students, who exploit her vulnerabilities, forcing her into complete submission. Made to hold a calligraphy brush between her lips and coerced into performing calligraphy, she gradually descends into becoming their sex slave, her dignity and spirit crumbling away completely.