The targeted murder of four officers is only the first in a series of attacks that leaves police scared, angry and, most disturbingly of all, vengeful. As Tom Thorne and Nicola Tanner dig into the reasons for the violence, a deeper darkness begins to emerge: the possibility that these murders are payback. The price paid for an unspeakable betrayal. To uncover the truth, Thorne will be forced to question everything he stands for. He can trust nobody, and the shocking secrets revealed by one terrible night will fracture his entire world.