Dept. Q episode 4 recap: a visit to Mhor and who is Sam Haig?

Dept. Q is Netflix crime drama following detective Carl Morck (Matthew Goode) as he deals with the guilt of a shooting that left his partner paralysed and a younger officer dead.

As Carl returns to work, he's instructed to launch Department Q, a new arm of the police tasked with reopening cold cases. His first case, a missing prosecutor called Merritt Lingard, which threatens to throw his entire world into turmoil.

Here's a recap of everything that happened in Dept. Q episode 4.

The episode starts with Merritt looking for William’s hat on the ferry. An older woman’s voice calls out her name. As Merritt turns to the woman, she’s wearing sunglasses and a scarf around her head. Suddenly, a man comes up behind her wearing the hat that William drew and puts a pillowcase over Merritt's head. Merritt wakes up in the sealed chamber for the first time. She panics, smashing the glass and asking after her brother. They start to play loud music into the chamber, silencing her.

Carl is talking to Dr. Irving. He’s ranting about Jasper and Dr. Irving looks in his file and says she didn’t know Carl had a son. He corrects her, stepson. She questions why Jasper doesn’t stay with his mother, but Carl says she travels a lot with work. She says she’s surprised that he'd look after him, but he says he did fight her on it. She says their time is up and Carl leaves.

At the station, DCI Bruce is still working on the Leith Park case. Bruce and Carl snipe at each other, but Carl says he’s trying to help him. Carl says that the shooter must’ve been inside when they got there as they couldn’t have come in the back door because it was blocked. Bins were piled up outside and a chair was in the way, so the officers would’ve heard someone come through.

But, Bruce says when they went to the scene, both those things had been moved. Carl says that the shooter may have left that way, but he didn’t come in that way. But, he says they’ve now found a man on the McDonald’s CCTV 25 minutes before they got there, so why would the man have left the scene before just to come back?

Carl thinks if that happened, there wouldn’t have been enough time for the man to get back, eat his food and come into the flat again to shoot them. Bruce says he’s negating his own argument. Carl says that the witness said she saw someone get into the car and drive towards the football pitch. When he asks Bruce what side the person got into the car, he doesn’t know. Carl says Bruce needs to go back and ask her. As Carl walks off, Bruce realises that there were two people at the shooting, not one.

Rose goes to visit Hardy in the hospital. She tells him she’s been brought onto the case, but only because she blackmailed Carl. Hardy says that Carl wouldn’t take blackmail and that he must want her to work with him. She says she’s going to Mhor. Hardy tells her to start with Harry Jenning’s family. He tells her to focus on that and he’ll be focusing on what happened in the weeks after Merritt’s disappearance.

At the chamber when Merritt was first taken, she looks around, noting all the signs on the wall about it being a pressurised space. It cuts to Rose making small talk with the constable in Mhor. She shows an interest in his military figurines. She then starts to ask questions about Harry Jennings. The constable says Harry had a temper. He thinks that it was just bad luck that William was home during the burglary and that there had been lots of other burglaries, but no one else had been at home during them. But, while Merritt left with her brother in the helicopter and never came back to Mhor, she did come back for Harry’s funeral. He says that Merritt and Harry were close.

When Rose asks to speak to Harry’s father, Clive. John says he’s dead. So, she asks to speak to Harry’s mum, Ailsa. He says she can try, but she’s not very social. John instructs his son, Colin, another policeman, to take Rose. As they drive, Colin says that his dad doesn’t like talking about the Lingards and the Jennings. He said that when Carl requested the case files from his dad, he looked through them all night and seemed upset.

So, Colin thought he’d have a look at them, too. He said one photo of the room William was found in, someone had circled something that was lying on the floor in black marker. A necklace. Colin thinks his dad circled it. Colin says he could scan the photo for her to see. Rose is thankful.

They arrive on a private property with hazardous waste signs posted up. It used to be the business that Clive Jennings ran. They head inside the static home on the site and ask after Ailsa, knocking on the door. They head inside and Colin thinks Ailsa must be at church where she works part-time as a bookkeeper. He offers to drive Rose over, but she says she needs to catch the ferry.

When Carl arrives home, his ex-wife Victoria and lodger Martin are talking in the kitchen. Victoria is wearing a flight attendant uniform and says she’ll need to go and catch a flight soon. Carl tells her that Jasper left and is staying with her mum. She says she was told over the phone and wants to know what happened. Carl says that Jasper was getting better, until Victoria played him the voicemail Carl had left her saying he wants to be alone. She said she played it to him to show him it’s not his fault, that it’s how Carl is.

She then explains that when Carl got hurt, Jasper stayed the entire time until he was out of danger. He asks her how she knows that and she tells him that her mum told her. He’s shocked to hear it, but she says that Jasper needs to know it’s not about him, it’s about Carl and his own mind. That when he says he would be better off alone in the voicemail, he meant it about himself, not Jasper. She goes to leave and says Jasper will come back soon enough, but Carl should think about what he comes home to.

At Dept. Q, Akram wants to hear about Mhor from Rose. She shows Akram the photo of the necklace circled on the floor from the Lingard robbery and assault that Colin sent over. It’s Lila Lingard’s necklace. It wasn’t stolen during the robbery, but Merritt came back for it on the day of Harry Jennings’s funeral. Another flashback to the chamber and the little door opens with supplies. Merritt starts to strip off to change and the lights get turned off.

At Carl’s, Martin is cooking him dinner because he wants to talk about Leith Park. Carl says he already does so with his therapist, but Martin says he doesn’t want him to talk to him about it, he wants him to talk to Jasper. He begins to tell Martin that the bullet went in one side of his neck and out the other. Martin says he knows. But, Carl says it did that after going through Hardy’s spine, which slowed it down and most probably saved his life while paralysing Hardy. He says if Jasper was scared of seeing Carl in the hospital, he isn’t going to want to hear what Carl has to say.

At Dept. Q, Rose hypothesizes that Jamie has something to do with Merritt’s disappearance since the boat shared the same name with the image on the cap. Carl says she’s assuming that they’re the same bird. She brings up Lila’s necklace and suggests Jamie was trying to get it back off of Merritt. Akram is looking through files sent over by the Crown Office of Merritt’s. He finds a note that suggests she was seeing someone as it invites her to meet in the same room and the same bed as usual. "Signed, S." Carl asks who packed up the files and Akram says it was her PA, Sabrine Perera. He brings her in to talk.

Sabrine says she was similar to Merritt and they fought against the rest. Akram wonders if she could survive in a difficult situation and Sabrine asks if they think Merritt is alive. Sabrine says she’d know if Merritt was alive and she isn't. Rose shows her the note from S. She doesn’t know who it’s from.

Sabrine says that the men in the office wanted Merritt, but she didn’t want any of them. She thinks the only person Merritt was possibly friends with was Liam, who worked on the Finch case with her. While he was happily married, Merritt thought of him as a "challenge". She says if Merritt had someone, it would be someone outside the office.

Carl and Akram go to see Liam. Stephen is in the pub with him, thanking his colleagues for a recent court win. Liam says he has to go as it’s his daughter’s birthday. So, they talk to Stephen instead. Carl starts reciting the note sent to Merritt with the sign-off, S. Stephen says it wasn’t him. Meanwhile, Hardy is looking at Egley House on his laptop. He then looks through photos of Merritt's expensive belongings.

Carl finds Liam on the beach after a swim. He asks him what he thought of Merritt. He says he never had a problem with her. Carl asks about Merritt’s PA saying Merritt thought of Liam as a challenge. He asks if she ever acted on it. Carl says that Merritt would get what she wanted and asks him if they had sex. He tries to deny it, but Carl sees through it.

He asks if his wife knows and he says no. He said it lasted a month and Merritt ended it. He said they would meet at the Prince’s Hotel. Carl asks if he sent her flowers and he says she would’ve hated that. She always paid for the hotel room, but it ended a year before she disappeared. Carl says he won’t put her in the file and as he goes to leave, Liam tells him that Merritt would check into the hotel as Lila Graham and she had a credit card in the same name.

Carl goes to meet Akram and Rose at the Prince’s Hotel. The assistant manager, Marcus, says he can’t help, but Carl isn’t interested. He asks instead how long they keep guest records for and he says five years. He says he can’t give out private data as it’s protected by law, but again Carl provokes him to release the data.

It shows that Merritt, as Lila Graham, stayed in the same room six times two months before she disappeared. She had assigned an authorised guest to sign for anything, meaning Liam signed to make it look like Merritt was never there. But, it wasn’t Liam Taylor who signed on the last time Merritt was there. It was a man called Sam Haig.

It cuts to another flashback in the chamber, the voice is asking Merritt, “Why are you here?” and that the truth will set her free. If she answers wrong, she gets another month to guess again. It cuts to Merritt in a hotel room. Claire texts her asking her to come home for William, but a man’s voice in the room asks her if she’s okay. It cuts back to the chamber and she’s offered her first chance to guess. She tries Sam Haig. The voice asks her what she did to him.

Again, it goes back to the hotel room and Sam Haig offers to teach Merritt how to climb. She says she doesn’t want to and he notices she’s already dressed. She says she has to leave and tells him that she’s going to Mhor to see her father. She won’t say how long she’ll be gone for. She says they’re only having sex, they’re not sharing information. As she goes to leave, he swears at her.

In the chamber, Merritt says to the voice that she used Sam and was unkind to him. Her guess is wrong, but the voice says that Sam Haig is dead because of her. They then tell her when she guesses wrong that her life will become more uncomfortable. The woman turns up the pressure in the chamber. A voice begins an announcement calling it a hyperbaric chamber. It explains that when the pressure increases, so does the heat. Oxygen will become denser and make it tougher to breathe. It’ll cause Merritt to tremble, sweat, hallucinate and become confused with headaches.

All episodes of Dept. Q are available to stream on Netflix.