A mother and her teenage daughter are found brutally murdered in a remote farmhouse. Reluctantly, clinical psychologist Joe O'Loughlin is drawn into the investigation when a former student, calling himself the 'Mindhunter', trading on Joe's name, has jeopardised the police inquiry by leaking details to the media and stirring up public anger. Joe discover links between these murders to a series of brutal attacks where the men and women are choked unconscious and the letter 'A' is carved into their foreheads. As the case becomes ever more complex, nothing is quite what it seems and soon Joe's fate, and that of those closest to him, become intertwined with a merciless, unpredictable killer.