A direct threat on Claire's life pushes her uncomfortably close to John, sending her fleeing to the Western Isles. Convinced she's being watched, Claire finds she can't outrun the darkness this time as Norrie, frightened for his daughter's safety, banishes Claire back to Manchester. To win her family back, Claire must solve the murders and trap her tormentor. John also faces mounting pressure to crack the case, as ambitious DSI Lola Keir dangles his pending misconduct investigation over him. She needs a clean arrest based on hard evidence; with Claire's reliability in question, John must dismiss her theory of a new killer and play by Lola's rules. Sidelined from the investigation, Claire attempts to get inside her stalker's mind. Her frenzied investigations lead her straight to into her target's path, igniting a dangerous line of communication that severely tests Claire's loyalties and professionalism. When a high-profile prime suspect re-emerges, Claire repeats a fatal mistake when she makes a promise she can't keep. Determined to end the violence, Claire entices John into a reckless mission that could cost them much more than his career. She believes it's a risk worth taking. But the explosive consequences of their rebellion threaten to launch a fresh wave of terror, and to drive the pair apart forever.