For the first time in my life, I have an enemy. For a long while I didn’t even want to take a walk for fear of running into her. I had vivid images of her and her family coming to harm—being run over, maybe, or gunned down at close range. A therapist friend told me this was quite normal under the circumstances, but none of it felt normal to me.

Can I understand what happened? Forgive? Maybe I could if I had been the victim, but it was my teenage daughter. A supposed friend who must have wanted her out of their group made up a horrifying tale about her, something the other girls in their circle knew to be an absurd lie. Parents and school counselors were called in. It tapped a primitive, protective instinct in me, and my body shook for an entire day. The lie was exposed, but it was too late: my daughter had lost her friends to the girl who had inflicted the casual cruelty—also typical, therapists tell me. This girl was powerful enough to make someone vanish with just a few false words. Poof! My daughter no longer existed at her high school. She disappeared into an eating disorder that she now sees was mostly a coping mechanism after this incident.

She had been harmed not just by a girl’s malicious behavior, but by learning that malicious behavior can triumph. She would have figured that out in time, of course, as we all do. And she will come across other deceptive narcissists lurking beneath other smiling exteriors. But she shouldn’t have seen it firsthand at 15 and had to endure two more excruciating years as one of the countless hordes of kids trounced by the bullies and mean girls who reign supreme in the teenage world.

My revenge fantasies have subsided. My daughter has moved on to college applications and the fervent desire to leave her small, stifling high school far behind. She has reconciled in some way with this girl, enough so that they can sit in the same classroom without tension. There is even a possibility they will end up at the same college. I told my daughter I would eat nails if that happened, but it was time for her to parent me with her wisdom. She refuses to allow this girl to affect an important decision. She instinctively knows what I can’t yet grasp: the negativity will continue to drag her down if she lets it. She has a whole life of new friends and interests ahead of her and does not want to tarnish it by carrying old wounds into new places.

I am doing my best to catch up with her thinking, but she is way ahead of me.