Retribution

Wesley Nevin was not gay. But a group of five high school bullies said he was. He was different from them; he was poor, and overweight, and his father had abandoned him and his mother when Wes was an infant. His persecutors were relentless; they called him names, they beat him and continually humiliated him. Every day for three years, he had endured their abuse. They made his ordinary life hell, and yet somehow he managed to carry on.
Then his mother committed suicide. It stopped the bullying, but it did irreparable damage to Wesley's psyche. The clock was ticking inside him, a time bomb waiting...

Fifteen years later, Wes is now the head doughnut maker at the local bakery. Life is good again, or at least, it is peaceful. And then she comes in; Rachael. She was one of them.
He recognizes her immediately, but she doesn't even notice him and completely snubs his attempted politeness. That's all it takes to trigger the horrific memories of his school days and send Wes on a homicidal spree for vengeance.

It's never too late for Retribution.