In the aftermath of a school shooting, the perpetrator’s loner best friend becomes a romantically involved with a popular girl who was injured in the incident. Their relationship is put to the test when he is forced to testify at an inquest that he had foreknowledge of the tragedy.

So he's too "insular" to notify the police of an impending mass murder. But he's not too "insular" to get romantically involved with a girl. And not just any girl; he, an outsider, has hookie up with an insider, one of the most popular girls in school.

Sorry, I'm not buying that.

I think your idea has the promise of exploring an interesting character dyad, but it seems like you're still in the brainstorming stage. Keep brainstorming, best wishes with the story.

Sounds interesting! I like your story idea.

Thanks.
I was toying with the idea that he had foreknowledge of the shooting, but due to his insular nature did not warn anyone... and now the guilt is eating at him....