High school kids in this small town are getting slashed and stabbed. And the masked killer keeps taunting Emma to stop him from killing even more. "Don't call the cops or tell anyone, or I will kill 'name of latest abductee'" he always tells Emma and her friends.

This genre always has protagonists making the most stupid decisions which place them in peril, and this series follows suit. It gets pretty old though because they really, REALLY use that trope too much.
They figure out that the killer is at a party and decide they should cut the power to the lights and the music. Yeah, when there is a knife wielding killer in your midst you cut the lights off, good idea. And when a group of your friends is trapped in a movie theatre with the killer, you split up and make it easier for him to kill you off one at a time. It really made it harder to watch the show when they did so much of that stuff.