Dark Descent

Paul Spector, a Belfast bereavement counsellor with a wife and two small children, keeps a second life. The series opens with him in a woman's flat, peeling off a balaclava after stalking the solicitor Sarah Kay. He breaks into her home, takes underwear and leaves a deliberate calling card. Sarah reports the break-in; the officers who attend, among them PC Danielle Ferrington, fail to persuade her to leave, and she stays.

Across the city, the Metropolitan Police superintendent Stella Gibson arrives in Belfast at the request of ACC Jim Burns to carry out a 28-day review of the stalled investigation into the murder of Alice Monroe, a 32-year-old architect. Working through the case photographs, she sees that Alice's body was posed and concludes the killer had done it before. She links the death to the earlier murder of the university lecturer Fiona Gallagher and argues that a serial killer is at work, a reading Burns resists, asking her to treat the case as a single entity. A second strand runs alongside rather than joining it: a drug dealer, Michael Lockwood, is shot dead in the Shankill, and a car stopped near the Falls Road yields a man named Terry McInturff carrying two concealed handguns.

Gibson rebuffs the journalist Ned Callan, who wants to make a story of her arrival, and gives DS James Olson her hotel room number at the end of a professional introduction. That night Spector tells his wife Sally Ann he is going out to his voluntary work on a suicide helpline, returns to Sarah Kay's house and strangles her while officers stand outside the building unable to get in, a control-room call checking on her welfare heard as she dies. The episode ends on the killing with Spector's face unmasked, so that his victim can see him. The series names him to the audience within minutes, and the reason he kills is not established in this record.

The episode's strength is that early identification. It turns the five hours into a study of a man and the woman hunting him rather than a puzzle, and the Guardian's preview called the device a gimmick that never feels like one. The weakness is the episode's patience. The Guardian's own complaint is that the plot can advance on Gibson's intuitive leaps rather than on evidence, and the slow first hour divided reviewers, with Den of Geek finding Spector dull at this stage.

As an opener it sets the series' formula rather than departing from it: the killer identified early, the institution a complicating factor, the first series ending without a resolution. It is also the only part of the series that had to establish its tone from nothing, and the post-Troubles Belfast setting and the argument about misogyny both begin here. The record won the 2014 Edgar Allan Poe Award for Best Television Episode Teleplay for Allan Cubitt, and the BBC renewed the show on 27 May 2013, during the first run. The reviews were largely favourable: the Guardian called the series one of the best things on the BBC in years, while the Telegraph praised both leads and objected to the blurring of attraction and danger. It drew 4.49 million viewers on BBC Two.