Satsuki Kirioka, a cleaning lady at a training facility, finds her daily routine shattered when a former student—her stalker since her days as a teacher—reappears by chance. Exploiting her past secrets, he rapes and humiliates her. An employee who secretly watches the assault is then forced into compliance, leading to further gang violence as other male staff members take turns assaulting her. Even as she resists their brutal advances, her lower lip glistens with wetness, betraying her body's involuntary response. Satsuki's gradual psychological breakdown, consumed by shame and helplessness, is portrayed in an intensely suffocating manner.