Law & Order: Special Victims Unit Episode 5.25 Head

A man is investigated for hiding a video camera in a public restroom for sexual pleasure. To escape trial, he reveals an incriminating clip. In the clip a middle school female principal commits statutory rape with her teenaged male student in said public restroom. When the incident is exposed, her ashamed student son attacks her raped student at their school as revenge. It is then learned the principal did it due to her brain tumor, which can be cured by surgery. However, it is known to be able to grow back. Therefore, she agrees to register herself as a sex offender as part of a plea bargain. But after learning she got pregnant by her student, she breaks the bargain to contact him.