Lynda La Plante introduces Detective Inspector Francis O'Neil (Fiona Shaw), one of the country's leading criminal psychologists. A deeply religious woman, she has devised a new way of approaching profiling, using her innate spirituality to confront the twisted minds of the most depraved killers. But when faced with the gruesome murders of two women found tied up and beaten to death - O'Neil must draw upon every last drop of faith and intuition as she battles a nightmare killer who always seems one step ahead. With no witnesses, weapon or forensic evidence, and cynical detectives such as Dl Glover (Colin Salmon) watching her every move, O'Neil becomes deeply affected by the intense pressure of the investigation. It seems the hunter risks becoming the hunted, unless she can quickly unravel the psychological clues that promise redemption - both for her and the victims.