The chilling finale of the Knock Knock series!

Cooper, Delilah and Riley are still coping with everything they endured.

The trio start receiving threats from a new killer only days after taking down the copycat that wreaked havoc and attempted to get their revenge on them while still in the hospital recovering.

After being released, Cooper and Delilah jump back into action right away, trying to solve the murders before it's too late. Immediately, they spot a pattern--this killer is targeting the neighbors of the killer's previous victims, and becoming much, much more aggressive, using any means necessary to get Cooper and Delilah and end them once and for all.

It doesn't take long for Cooper to realize that the killer is much, much closer than he thinks.