After a teenage girl's perplexing suicide, a classmate receives a series of tapes that unravel the mystery of her tragic choice.

Over the last ten years, technology has transformed almost every aspect of our lives before we've had time to stop and question it. In every home; on every desk; in every palm - a plasma screen; a monitor; a smartphone - a black mirror of our 21st Century existence.

Twenty years ago, a series of tragic events almost ripped the blue-collar town of Millwood apart. Now, in the present day, a group of disparate teen girls finds themselves tormented by an unknown Assailant and made to pay for the secret sin their parents committed two decades ago, as well as their own.

Based on the stories of Stephen King, the series intertwines characters and themes from the fictional town of Castle Rock.

As a killing resembling a cold case resurfaces in a small town, the chase for the truth falls on two policemen who each harbor secrets of their own.