Walter Klemmer, an engineering student, is introduced very early on. He comes early to class and watches Erika perform. He eventually becomes Erika's student and develops a desire for his instructor. Erika sees love as a means of rebellion or escape from her mother and thus seeks complete control in the relationship, always telling Klemmer carefully what he must do to her, although she is a sexual masochist. The tensions build within the relationship as Klemmer finds himself more and more uncomfortable by the control, and eventually Klemmer beats and rapes Erika in her own apartment, her mother in the next room. When Erika visits Klemmer after the rape and finds him laughing and happy, she stabs herself in the shoulder and returns home.