As a violent storm blew into Morfa Halen, the residents formed a search party to look for missing James Rees. Of course, the unspoken fear was that he’d been killed – just like murdered school children Nessa and Cefin before him.

In emotional scenes, Jackie Ellis and DI Eric Bull finally discovered the horrifying truth behind the crimes that haunted Morfa… Which left Bull fighting for his life and Jackie facing an unbearable choice. In a final reckoning among the salt marshes, the storm reached its peak, and Morfa’s darkest secrets were laid bare.

It was a fitting ending to a brilliant series, and we can’t be the only fans hoping for a series 2. So here’s the ending of Under Salt Marsh unpacked.

***Warning: spoilers from the ending of Under Salt Marsh ahead***

What happened in the Under Salt Marsh ending?

The final episode began where the tense penultimate instalment had ended… With James Rees missing in the storm, and his uncle Dylan caught wearing a very incriminating white hazmat suit.

By this point, viewers knew that Dylan Rees was somehow connected to the dodgy deliveries of illegal waste coming into Morfa Halen. He signed for the deliveries every time.

We also knew that Dylan’s hair was found on James’ dead body. Crucially, when Jackie finally found out about the evidence stacked up against Dylan, she went to confront him. And he returned home wearing the very same type of white hazmat suit drawn in the pictures by Nessa and Cefin before they died…

Of course, Jackie soon learnt that Dylan WAS involved in burying toxic waste in the sea wall. But he was not a murderer. She begged him to tell her who else could have worn a white hazmat suit with his DNA on it. And the answer shocked Jackie to the core, as it was someone in her own family.

Who killed Cefin and Nessa?

Mac Jones murdered both Nessa Taman and Cefin Rees. In sickening scenes, he told Jackie he “didn’t have a choice”. And, as we’d suspected, it was all linked to the illegal toxic waste being brought into the town.

Dad of one Mac, described as a family man with aspirations of reinvigorating Morfa, was in charge of the rebuilding of the community funded sea wall. But instead he started using toxic waste to build the sea wall.

Jackie’s secret boyfriend Dylan worked for Mac at Sunnyside, rebuilding the wall. Only Dylan and Mac knew about the toxic waste being used. At Sunnyside, the pair had been recycling hazardous waste. They crushed it and put it into the concrete for the sea wall. Why? We can only assume it was to save money, instead of using more expensive materials.

That was why Dylan had told his nephew James Rees and his best friend Cefin about the legend of the Black Sow. He thought it would scare them so they wouldn’t venture near Sunnyside – and the toxic waste. But tragically, it had the opposite effect. Cefin went looking for the Black Sow. And met his death.

Why did Mac Jones kill Cefin and Nessa?

Both Nessa and Cefin died because they’d inadvertently stumbled upon the illegal toxic waste in Morfa. Nessa has fallen into the waste and been injured, while Cefin was at Sunnyside the day he died looking for the Black Sow. He also suffered injuries after finding the dangerous waste.

Mac later admitted: “I found Nessa and she was hurt. She would have died from her injuries.” Talking about Cefin, he added: “[The toxic waste] had gone through his wellies. I was only trying to clean him up. But he kept shouting about it, he wouldn’t shut up. I had no choice.”

Of course, Mac’s wife Ira Taman was the sister of Jackie Ellis’ brother-in-law Nev. Jackie’s sister Lydia married Nev Taman, making Ira Jackie’s sister-in-law, and Mac her brother-in-law. So Mac had killed his own niece. He suffocated Nessa, and drowned Cefin to silence them after they accidentally found the waste and got hurt.

He’d also been responsible for the landfill on Solomon’s farm. Although it wasn’t revealed if Mac had also killed farm worker August Antonov, we’re confident that he did.

Under Salt Marsh ending: Mac stabbed Dylan and tried to escape

In a thrilling denouement, Jackie confronted Mac at his house. Cornered, he lashed out with a knife, stabbing Dylan in the process. He promptly legged it into the marshes, hoping to make his escape.

But Jackie and Eric weren’t going to let that happen. They both followed him into the marshes, where Mac slashed at his own wrist in an attempt to kill himself rather than get arrested.

In tense scenes, he admitted to his crimes, and goaded Jackie into letting him kill himself. He told her: “Nessa screamed for you. She screamed for her mother and father, and for you. And what’s so funny is that Cefin did too.”

Boiling with rage about her niece Nessa’s fate, Jackie launched herself at Mac pushing his head under the water of the salt marshes. It looked like she wouldn’t stop until she’d killed him, but she stopped herself just in time. All the while, Di Bull had been watching and didn’t attempt to stop her. By this point his friendship with Jackie meant more than his job.

Mac, alive despite the slashes in his wrist, was subsequently arrested and held in custody until the storm passed and he could be taken to prison.

Under Salt Marsh ending: What happened to James Rees?

At the beginning of the Under Salt Marsh finale, James Rees was missing. But, unlike Nessa and his friend Cefin, James was safe. Well, as safe as you be in an apocalyptic storm.

The nine-year-old had gone to Sunnyside – the last place he’d known Cefin to be alive. And thank goodness he did go there. At the building site of the sea wall, he found DI Eric Bull in a very dangerous predicament.

Viewers had seen DI Eric Bull visit Sunnyside to investigate the toxic waste. But, when Mac found him snooping around there, the pair fought and it ended badly for Bull. Mac locked him in a room on site which was fast filling with water in the storm.

Luckily, James arrived in the nick of time and saved Bull from drowning. It partly made up for not being able to save the life of his best mate Cefin.

What was the trauma in DI Eric Bull’s past?

As DI Eric Bull faced imminent death in a locked room with rising water, he pleaded with young James Rees for help. And in doing so, he told the boy about his own childhood friend called James Cook.

He said: “My best friend James Cook was called James when I was young. He was my best friend in the world. I loved him, I really loved him. He died when he was 14; we were kids. But we liked going into buildings like this. And where we grew up, it wasn’t like Morfa; it was dangerous. He got himself into a really dangerous situation, and I was too scared to help him. So I know how that feels. And I know how you must feel about Cefin.”

He went on to say: “I think about him him every day of my life. Because he was a star. He was a superstar.”

This also helps to explain why Eric was so loyal to Jackie. In a previous episode, he’d referred to her as his only other friend apart from James.

Did DI Eric Bull keep his job?

In episode 5, DC Jess Deng threatened to report DI Eric Bull for his handling of the investigation. She’d called out his “toxic” relationship with Jackie, which she believed had compromised the case. She was right, of course. But DI Eric Bull was trying to correct the wrongs of his past.

In the season finale, Bull told Deng to report him for his involvement with Jackie Ellis. He also revealed he would be honest about it in his report. He insisted he couldn’t follow police protocol on this case because he “needed” Jackie’s help.

In response, Jess Deng said: “They’d be an investigation, and you’d be stood down. It could be gross misconduct.”

Although the future of his professional career looked unclear, his personal life looked a little rosier. Eric told Environment Institute worker Gareth Morgan that he was sticking around in Morfa – for a little while at least. And Gareth would be there too, organising the clean-up of Morfa. It was clear there was potential for a beautiful relationship between them…

In a later conversation with Jackie, he told her he eventually planned to get away. He said: “There are some really beautiful things out there, and I really want to see them.”

Their friendship restored, it was an emotional moment between two people who were probably more alike than they both realised.

What else happened in the dramatic ending of Under Salt Marsh on Sky Atlantic?

• The storm finally ended, leaving Morfa Halen’s residents battered and bruised. After taking shelter on Solomon’s farm, they returned to their homes – or what was left of them. The entire town had been flooded.
• Tragically, pub landlady Carys Northam did not survive the storm. Osain found her dead body floating in the water, after she refused to leave her pub behind.
• Jackie Ellis finally admitted that she was pregnant to the doctor, and underwent a medical examination. Jackie was visibly moved when she listened to the baby’s heartbeat on a stethoscope. And she asked the baby’s father Dylan to listen, too. It looked like the couple would become a family together and get a happy ending of sorts.
• The closing moments revealed that Ned Bevan was still missing, having fled Morfa. Viewers knew that Ned was the person responsible for leasing some of Solomon’s farm for landfill. He’d also found Nessa’s body in the quarry, and decided to bury it “for the good of the farm and his family”. Even his own dad Solomon called him a “coward”.

Is there a series 2 of Under Salt Marsh?

Sky Atlantic has not confirmed or denied if there’ll be a series 2 of Under Salt Marsh.

Although the series worked beautifully as a stand-alone six-parter, we’d be on board for another series. It was without doubt the best crime drama of 2026 so far, and the Under Salt Marsh cast were sublime.

We’d love to see the friendship between DI Eric Bull and Jackie Ellis again, as well as follow Jackie’s progress as a mum. You knows, perhaps Eric and Gareth might also settle down together?!

Hopefully, after the success of series 1, another set of episodes will be commissioned. Watch this space for more news if and when we get it.

Read more: Under Salt Marsh on Sky Atlantic: Filming locations including ‘dramatic UK landscapes’ and if Morfa Halen is a real place

Under Salt Marsh is now available to watch as a boxset on Sky Atlantic.