Once a witness, Always a witness

"Y/N L/N, Can you tell us what you saw?"

That was what you were asked 3 years ago on your 18th birthday. You had witnessed murderers from horror movies come into your house and kill everyone there, you wre stabbed in the frontal lobe and left with the inability to feel emotions, while yes you can feel, You can't feel strong negative emotions such as Anger or Sadness. So what happens when the murderers you saw 3 years ago come back?