Zack Tripler, a psychiatrist, admits to the hospital Youssef al Saud, an agitated young Saudi American, in the midst of what appears to be a psychotic break. Youssef has been hearing voices and was found hiding with his laptop in the woods from unidentified assailants whom he believes are trying to kill him. He’s found coded messages on the laptop that he suspects portend a terrorist plot.

When Youssef is found dead, either by suicide or murder, Zack develops symptoms similar to Youssef’s, hearing voices and catching glimpses of his dead patient, whom he believes is trying to kill him, then witnesses the murder of another of his patients. He becomes entangled with Youssef’s widow Jamilah in her efforts to solve the mystery of her husband’s death and the coded message on his computer, but nothing in Zack’s world is as it appears as he swings between concern for her safety and suspicion that she is responsible for Youssef’s death and part of the terrorist plot that he suspected.

Zack narrates his own story, his descent into madness, and the terror he endures as he struggles to hang onto the last remnants of his sanity.