David Walker, the victim of a 26-year-old murder being investigated by detectives Cassie and Sunny, had a dark life. When Sunny follows up with a friend of David’s who said David was raped as a child, the friend speculates that that early trauma is what led to David’s wild behavior: prodigious drinking, drugs, and use of prostitutes, including an interest in S&M. David also supposedly went to the home of the teacher who abused him as a child, confronted them, and was threatened in turn.
David isn’t the only one with a traumatized past. Colin Osborne reluctantly reveals to Cassie and Sunny that the reason he left banking around the time of David’s death is because he had a breakdown and spent time in an institution, being viewed as a danger to himself – but he has kept this from the agency overseeing his adoption with his partner Simon of the young Flo. The detectives have followed up with Colin because they have unearthed photos from a local Tory political office of Colin with David, but Colin claims not to remember David.
Colin may be selectively editing his memories, however – Simon accuses him of keeping things from him. And a former colleague, after receiving legal advice, tells the detectives that Colin left banking after being charged with sexual assault by a temp. The case was handled internally, so there is no police record.
Marion is even worse than Colin about hiding things from loved ones. An address found among David’s things at the time of his death leads the detectives to Marion’s mother’s home. She and her husband were abroad at that time – but Marion did “break in” then. After Marion is questioned by the police, she leaves a furious voicemail for her mother and sister. “What did you tell them?” she yells.
Marion brusquely brushes Cassie off during her interview. She doesn’t remember David, she was homeless and had a key to her parents’ home at the time so she lived there while they were gone. When Cassie brings up an arrest for assaulting a police officer at a demonstration, Marion becomes defensive and storms off. The detectives learn the demonstration was for the IRA, and that Cassie lived with an IRA activist who later served time for bombings.
Marion’s husband Tony doesn’t know about any of this, and he’s getting tired of the wall she keeps between them. She’s already accused him of reporting her personal calls with Zoe, one of her teenaged cancer patients, but it turns out Zoe was the one who told her parents. When Marion goes to the pub after her trying police interview, Zoe finds her there and tries to comfort her over a drink, but Marion cruelly lashes out. The next day, Zoe has disappeared and Marion is suspended for a period for giving her alcohol – Zoe reported it in her diary. Zoe does eventually text her parents, but is still at large.
Marion finally reveals her long-gone IRA ties to Tony, but he doesn’t take it well and she simply walks away from the difficult conversation. He later tells her that if she wants their marriage to survive, she has to open up to him. Signs aren’t good that she will: he certainly doesn’t know that she once asked her IRA roommate to kill David, who was a Tory party organizer (the detectives track down the roommate, who tells them this), and she also hides from Tony a meeting with Colin and Sara Mahmoud.
None of this trio tells their partners about this clandestine meet-up. Sara has at least leveled with her husband Hassan about her past as a prostitute. While Hassan is distraught – “You’ve broken my heart," he says – he becomes caring and supportive after an initial outburst of yelling. Unfortunately, the couple’s youngest son overhears, and, confused and upset, tells his friend. Soon the Mahmoud’s whole mosque knows, forcing Hassan and Sara to tell their two other sons. The oldest is furious at his mother; the middle is enraged at the youngest for spreading the information.
And Sara’s connection to David? The day she sent him her address, she went to the hospital with a dislocated jaw. Perhaps the S&M got out of hand? She tells Cassie and Sunny that she doesn’t remember.
Sexual violence would seem to be consistent with David’s behavior. The woman from the Tory party office who sourced photos of David and Colin together eventually calls the police again to reveal a traumatic secret: when she was 12, David raped her.
This revelation transforms the investigation and divides Cassie and Sunny. Cassie doesn’t excuse David’s crime but believes he deserves some understanding because of his own childhood trauma; Sunny, disgusted, rejects outright any sympathetic urge.
There is now another possible motive in David’s murder: someone abused by him as a child might have killed him, and both Sara and Colin have dysfunction in their lives consistent with childhood trauma. The detectives begin looking at places David volunteered – a hospital, a reform school, a children’s charity. The hospital and charity report rumors but no evidence, but someone who attended the school says David did abuse kids – and that he sometimes brought them to gatherings in which groups of men offered troubled children drugs and alcohol, and sometimes raped them. It was never reported, because who would ever believe kids at a reform school?
Colin thought a similar rationale would protect him from more blackmail by Flo’s birth mother and her boyfriend after he paid them ₤5,000 – who would ever believe a crack addict? – but when the mother comes to ask for more money and Colin storms off, he makes a fatal mistake: he leaves his phone. She swipes it. Unfortunately, it’s not password-protected, and it has a text about the police investigation into David’s murder. Soon, Colin and Simon are being asked for twenty grand. If they don’t pony up, the adoption agency will find out about the investigation, and they’ll lose Flo – it doesn’t help that Colin, distracted by all this drama, has already forgotten to pick up Flo from school once.
Just as Colin tried to protect Flo, Paul Nixon is making a drastic decision to protect his daughter Becca. He and Becca are leaving his wife Tessa for a while. Tessa, David’s wife, has been taken off active police work because of the investigation and is beginning to scare Paul with her brooding, closed-off response to the whole situation. But it’s her and David’s son Jason who’s the impetus for Paul leaving with Becca.
Jason is taking the investigation badly: he’s already ranted at Becca that he might want to hurt someone, and he slapped Cassie when she told Tessa about the charge of rape against David. (Cassie, ever empathetic, dismisses it, and Jason is apologetic.) Given that David abused children, who knows what Jason could do? Who knows what any of these people could do?