S1 • E1
David Whitehead, an international television reporter, returns to his home town of Southcliffe in the wake of a major tragedy. Reclusive handy-man Stephen Morton, known as the Commander and carer to an elderly mother, has gone on a motiveless killing spree. Some time before the event Stephen had befriended Chris Cooper, a young soldier returned from Afghanistan, claiming a common military background. Stephen takes the lad on military manoeuvres though Chris is perturbed by the older man's excessive zeal, especially when he is injured by Stephen, which ends the friendship. Later Chris's family beat him up and he realizes that he is being reviled. This tips him over the edge and he embarks on his murderous spree, his first victim being his mother.
S1 • E2
As the news breaks that fifteen people have died in the shootings David drives to Southcliffe, telling colleague Anthony the town holds bad memories for him. In the days before the violence broke out Claire Salter, social worker to Stephen's mother Queenie, notices his isolation and suggests he socialize. Though they have a daughter Anna, shortly to leave home for university, Claire and husband Andrew consider IVF for a second child as Claire has difficulty conceiving. Pub landlord Paul Gould, to the disgust of his brother Geoff, is having an affair with a younger woman who wants them to leave Southcliffe though he refuses. Later he will discover that his family will be among Morton's victims. Claire is also worried when Anna, out jogging, fails to answer her mobile phone.
S1 • E3
Claire and Andrew learn that Anna was one of the victims as were Paul's wife and children. Whilst Claire cannot bear to see her daughter in the morgue Paul, consumed with guilt over his affair, goes to pieces, pouring petrol over his house and taking his niece to play on the railway lines before indulging in dangerous activities on a motorway bridge. At his wife's funeral he bans the wearing of black and insists the Wedding March be played. David explains to Anthony that, as a child, he played with Stephen Morton, who was always very odd and obsessed with creatures on the marshes. He tries to interview locals, including the man next door to Morton, the pub landlord and Morton's sister but they all have little to say. It transpires that David's father died in an accident which claimed others and David was bullied as the son of a man branded a murderer. In the light of this his television interview with Andrew is damning of Southcliffe and he foolishly accuses the townsfolk of being complacent in not recognizing Morton's potential as a killer. This is not well-received and he is vilified when the report is shown on YouTube.
S1 • E4
A year has passed. David's drunken rant has cost him his job and his marriage and he is living in a bed-sit when he receives an anonymous letter reading Happy Returns, leading him to wonder if Morton is still alive. It determines him to return to Southcliffe though Anthony refuses to accompany him. Claire is still grieving, having turned Anna's room into a shrine and obsessing about Maria, a friend of her daughter whom she believes to be the victim of sex-slavers. It takes a while for Andrew to ultimately get through to her. Chris has not rejoined the Army, staying in the town and, whilst he is cordial to David, his family is abusive . After discovering that his hotel room has been broken into David begins to suspect that Chris is not the outwardly friendly young man but a very troubled youngster and finds himself having to act, not only to avoid further bloodshed but to redeem himself for his past behaviour.
Stephen Morton
Claire Salter
David Whitehead
Anna Salter
Andrew Salter
Chris Cooper
Louise Cooper
Paul Gould
Jacqui Whitehead
Anthony