16-year-old Mark meets local girl Rachel on the internet, he begins an intense online relationship. He quickly finds that he’s besotted, that he’ll do anything for her, even befriend her awkward, loner brother, John. When Rachel, who is trapped within the grips of a possessive boyfriend, is murdered, Mark and John make plans to avenge her death. Their actions draw the attention of a secret government department as they unwittingly stumble upon an ongoing operation. Soon Mark is recruited to commit a crime that made British legal history.

Walter Sparrow is an animal control officer that becomes obsessed with a mysterious book that seems to be based on his own life. As soon as he opens the book, he notices strange parallels between what he reads and what he's experienced. But now he's worried that a fictional murder might materialize.