Killers by Nature, concerns two recent graduates, Jeffrey Mordrid and Cory Buckner, who plan to prank an old high school bully who relentlessly picked on them and beat them up. The prank goes awry and they accidentally kill the bully. So they try hiding the body and in the meanwhile run into another bully from high school who pisses them off. Then they kill him and by this point, notice they get a kick out of murdering. Thus begins their journey to kill every bully whoever picked on them.