The 2026 series Under Salt Marsh is a slow-burning crime drama set in the fictional coastal village of Morfa Halen. The show blends murder mystery with environmental tension, family secrets, and a looming natural disaster that feels just as dangerous as the killer hiding in plain sight. Across six episodes (each between 45-50 mins), the story follows Jackie Ellis, a former police officer turned schoolteacher, and DCI Eric Bull, the man she once trusted and now deeply resents. When a young boy is found dead in the marsh, old wounds are ripped open, especially because the crime seems connected to a three-year-old case involving Jackie’s niece, Nessa. As the sea rises and a brutal storm approaches, the truth slowly surfaces. By the time the final episode ends, justice comes at a heavy emotional cost, and Morfa Halen is left forever changed.
In this article, I will break down the thriller miniseries. Please note there are major spoilers throughout, so it is best to watch Under Salt Marsh before if you want to avoid any surprises.
Under Salt Marsh (TV Series 2026) Episode 1 Recap:
The series opens with a haunting image as we are introduced to Jackie Ellis seeing a body lying face down near cornfields. She rushes toward it in panic, but then she wakes up. This moment from her memory is tied to her past, which still has a tight grip on her life.
In the present day, Jackie works as a schoolteacher in Morfa Halen. She is kind and patient with her students, and the children trust her. One day, a troubled man named Osian storms into school grounds and grabs a child named Cefin. He rambles about the end of the world and environmental collapse. Jackie calmly talks him down and sends him away. The town is already tense because a major storm is approaching. Officials warn that sea levels could rise by five to six meters. The community has raised money to build a sea wall, but nobody knows if it will hold.
Later that night, Jackie makes a horrifying discovery where she finds Cefin’s body face-down in the marsh water that leads her to a complete breakdown. She calls the emergency services and then takes on the painful task of informing his parents, Shelley and Danny. Jackie used to be a police officer, so she wants to handle it gently instead of letting strangers break the news. DC Eric Bull arrives to lead the investigation with his partner Jess Deng. Eric and Jackie share a complicated history from their time working together but there is obvious tension between them. Jackie even tries to have him removed from the case.
The investigation quickly raises strange questions. Cefin drowned, but there are traces of salt water on his body even though the ditch is far from the sea, that suggests the body was moved. A stray hair is also found that does not belong to Cefin. Meanwhile, we also learn that Jackie is secretly pregnant and the father is Dylan Rees, a man she has been seeing quietly. The episode ends with Jackie looking through old belongings of her niece Nessa, who died three years ago in a case Eric once handled. In Nessa’s sketchbook, Jackie sees a drawing of a man in a white suit. Later, we learn Cefin drew the same figure which chills Jackie.
Under Salt Marsh (TV Series 2026) Episode 2 Recap:
Episode 2 expands the suspect list and deepens the emotional conflict between Jackie and Eric. Eric questions Osian at the local pub. Osian talks about environmental destruction and claims people should not have children. He seems unstable, but witnesses confirm he stayed at the pub during the time of Cefin’s death. The police find more evidence that Cefin’s drowning was not an accident. There is an incomplete handprint and Cefin’s blue wellington boots are missing. The route between the sea and the ditch runs past the woods where Nessa’s body was once discovered. The similarities between the two cases grow harder to ignore.
Jackie privately questions James Rees, Cefin’s best friend and Dylan’s younger brother. James identifies the “man in the white suit” as Kieran Benbow, a reclusive beekeeper who lives on Spider Island. Jackie becomes convinced that Kieran is involved. We also learn a painful truth from the past. In Nessa’s case, Eric accused Lydia, Nessa’s mother and Jackie’s sister, of killing her own child. That accusation shattered the family and destroyed Jackie’s trust in him. If these cases are connected, it would mean Lydia was wrongfully accused.
At a beach memorial for Cefin, tensions explode. Danny confronts Kieran with a shotgun after learning Kieran is Cefin’s biological father. Danny feels betrayed and insecure. Before tragedy strikes, Eric intervenes and stops him. By the end of the episode, Eric and Jackie realize they may need to work together despite their history. There is talk of waste buried near an old quarry. The question becomes clear. Why would Cefin go near that dangerous place?
Under Salt Marsh (TV Series 2026) Episode 3 Recap:
In Episode 3, the environmental angle becomes more serious as we see Eric investigating a landfill site, searching for sodium hydroxide, which could explain chemical burns found on Cefin. Jackie continues teaching but is visibly shaken. James finally admits that he and Cefin were at Solomon Bevan’s farm the day Cefin died. Cefin had nightmares about a creature from Welsh folklore called the Black Sow. He wanted to confront his fears. At the farm, workers are seen wearing gloves, which catches Eric’s attention. A Romanian farmhand named August Antonov becomes suspicious, especially since he has been sending large amounts of money back home.
Jackie speaks to other children and uncovers bullying in Nessa’s past. Nessa had been threatened into silence. That detail adds another layer to the mystery. Late in the episode, police discover Nessa’s body buried at the landfill. She had been there for three years. Jackie is devastated. Eric informs Lydia, reopening wounds that never healed. Laboratory results reveal that the stray hair found on Cefin belongs to Dylan Rees. That information threatens Jackie’s personal life and the investigation itself.
Under Salt Marsh (TV Series 2026) Episode 4 Recap:
Episode 4 shifts suspicion toward Solomon Bevan as he confesses that he found Nessa’s body years ago but reburied it to protect his family and farmland. He wrapped her body in tarpaulin and kept quiet. Autopsy results reveal that Nessa was suffocated, not burned to death. Soil and plastic were found in her lungs. The method matches Cefin’s death. The same killer is responsible.
Eric struggles with his emotions. He confronts Solomon harshly. Meanwhile, Jackie learns that body camera footage shows she once struck Eric after he used her information to arrest Lydia. That incident led to her dismissal from the police force. Jess pushes the investigation forward and questions August about hidden payments. He admits that waste is still being brought into the village by truck during low tide. As a severe storm warning is issued, tensions rise even higher. That night, August is found dead in rising rainwater. Another drowning. Another silence.
Under Salt Marsh (TV Series 2026) Episode 5 Recap:
Episode 5 turns things as August’s death appears suspicious. Evidence suggests he was trying to warn authorities about illegal waste dumping. CCTV footage shows someone setting his caravan on fire. Jackie questions Osian again, who admits he followed Cefin after school but insists he went home afterward. James finally confesses that Dylan warned them to stay away from certain areas or the Black Sow would get them.
Ned Bevan disappears, fearing he is next. Solomon admits that Ned originally found Nessa’s body with August and decided to bury it for the family’s sake. Jackie confronts Ned at the dock. He pushes her, and she hits her head. Eric is furious at her interference. He reveals that Dylan’s DNA matches the hair found on Cefin. Meanwhile, Jess uncovers documents showing Dylan was involved in sea wall deliveries. Eric discovers that illegal waste is hidden inside the sea wall structures. The storm traps everyone on the island. Then Jackie finds Dylan wearing a white hazmat suit.
Under Salt Marsh (TV Series 2026) Episode 6 Recap:
The final episode of Under Salt Marsh delivers the truth where Jackie confronts Dylan about the suit and the hair evidence. Dylan explains he was cleaning toxic waste and that Mac, another worker, also used the same suit. Eric investigates an abandoned theme park called Sunnyside and finds barrels of hazardous waste. The waste was crushed and hidden inside sea wall concrete explaining everything. Cefin discovered the toxic site. Since his boots were burned by chemicals, he panicked.
Under Salt Marsh (TV Series 2026) Ending Explained:
Who murdered Cefin in Under Salt Marsh?
Mac is revealed as the killer. He tried to “help” both Nessa and Cefin after they were exposed to toxic waste. When they screamed for Jackie, believing she could fix it, Mac silenced them permanently. He believed death was kinder than suffering. Mac confesses in the marsh as the storm rages. Jackie nearly drowns him in rage but stops herself, choosing justice over revenge.
The ending of Under Salt Marsh (TV Series 2026) shows that the storm finally passes and the village is flooded but still the spirit is alive. Eric tells Jess he will include his own mistakes in the official report. He decides to leave the police force. On the other hand, Jackie accepts her pregnancy, Dylan survives his stabbing. In the end, we see the town coming together in the aftermath, though Ned remains missing. The episode ends with Eric and Jackie sitting together as they forgive one another.
