Mayumi Kasuga has separated from her husband and is striving for independence as a life insurance sales agent. However, struggling to secure contracts, she finds herself burdened with daily stress. One day, through a friend's introduction, she visits a private residence. There, she meets a man living alone who suddenly knocks her unconscious and takes her to his private room. He forces anal sex upon her, causing unbearable pain that makes her scream before losing consciousness. Yet both Mayumi and this man carry deep traumas related to anal experiences from their pasts. As the two confront and accept their painful memories, something within them begins to change.