Gillian Anderson is DSI Stella Gibson, in Belfast to conduct a review into a high profile murder case. She quickly realises that the case is linked to others and that there is a deadly serial killer at large. Jamie Dornan is Paul Spector; husband, father, grief counsellor, serial killer, who chillingly selects and stalks his female victims. This chilling drama is a study in obsession: one man’s desire to kill, one woman’s quest to stop him. As it moves towards its inexorable conclusion, the rules of this deadly game of cat and mouse shift time and time again.