Under Salt Marsh: Everything to Know About Sky’s Gripping Welsh Crime Drama
A storm is closing in on a small Welsh community, and with it comes a mystery that has remained buried for three years.
That is the unsettling premise behind Under Salt Marsh, Sky’s six-part crime drama starring Kelly Reilly and Rafe Spall. Set in the fictional coastal town of Morfa Halen, the series combines a murder investigation with a portrait of a community struggling with grief, guilt and long-held secrets.
The story begins when former detective Jackie Ellis, now working as a teacher, makes a shocking discovery during a once-in-a-generation storm. What she finds brings an old case back into focus and forces her to confront the professional and personal losses that drove her away from the police.
The series launched on Sky Atlantic and NOW on January 30, 2026, with its first two episodes released together. The remaining four episodes followed weekly, with the finale arriving on February 27.
What is Under Salt Marsh about?
At the heart of Under Salt Marsh is an unspeakable crime in Morfa Halen, a close-knit Welsh community where people have spent years believing they know and trust one another.
That sense of security begins to unravel when Jackie Ellis discovers the body of one of her pupils. The discovery is particularly devastating because it appears to reopen the wounds of a three-year-old cold case, the investigation that previously cost Jackie both her career and the trust of her family.
Her discovery brings her former police partner, Detective Eric Bull, back into her life.
The two are forced to work together despite the history between them. As they begin to investigate, they uncover secrets that have remained hidden within Morfa Halen, while the approaching storm threatens to destroy crucial evidence.
The official premise describes Jackie and Bull as being drawn into an investigation that will shake the town to its core. Their task becomes a race against both time and the weather as they attempt to understand what happened and determine who could have committed such a devastating crime.
The series gradually expands beyond the central investigation, exploring grief, mistrust and the pressures placed on a community when people begin to turn against one another.
Kelly Reilly leads the cast as Jackie Ellis
Kelly Reilly takes the central role of Jackie Ellis, a former detective who has left the police behind and become a teacher.
Reilly will be familiar to many viewers from Yellowstone, where she played Beth Dutton. Her other television credits include True Detective, Britannia, Black Box and Above Suspicion.
In Under Salt Marsh, Jackie is very different from the confident and formidable characters Reilly has played elsewhere. She is a woman carrying the consequences of a painful past while trying to protect the community around her.
Her return to the investigation becomes unavoidable after her discovery connects the present-day crime with the unresolved case that changed her life three years earlier.
Rafe Spall plays Detective Eric Bull
Rafe Spall stars opposite Reilly as Detective Eric Bull, Jackie’s estranged former police partner.
Spall has moved comfortably between comedy and drama throughout his career. He has appeared in Trying, Pete Versus Life, Roadies and Black Mirror, as well as films including The Life of Pi and Jurassic World: Fallen Kingdom.
Bull returns to Morfa Halen to investigate the new crime, but his professional reunion with Jackie is complicated by everything that happened between them in the past.
Their uneasy partnership becomes one of the central relationships in the series as they attempt to put aside old mistrust and uncover the truth.
Jonathan Pryce and the supporting cast
The series has a substantial supporting ensemble, led by Jonathan Pryce as Solomon Bevan.
Pryce, known for roles in The Crown and Slow Horses, is joined by actors including Naomi Yang, Brian Gleeson, Harry Lawtey, Dinita Gohil, Kimberley Nixon, Mark Stanley, Dino Fetscher, Lizzie Annis, Rhodri Meilir and Julian Lewis Jones.
The wider cast includes:
- Naomi Yang as Jess Deng
- Harry Lawtey as Dylan Rees
- Dinita Gohil
- Brian Gleeson
- Kimberley Nixon
- Mark Stanley
- Dino Fetscher
- Lizzie Annis
- Rhodri Meilir
- Julian Lewis Jones
The ensemble helps flesh out Morfa Halen and its interconnected residents, with the investigation gradually exposing tensions that have been hidden beneath the town’s close-knit surface.
A fictional Welsh town with a very real sense of place
Although Morfa Halen is fictional, Wales plays a major role in the identity of Under Salt Marsh.
The series was filmed entirely in Wales, with the North Wales coastline providing much of its visual character. The production received support from the Welsh Government through Creative Wales.
The setting is more than scenery. The marshland, coastline and changing weather are closely tied to the story.
Writer and director Claire Oakley was inspired by the North Wales landscape while developing the series. Sky has also revealed that Shell Island on the Mochras peninsula, near Harlech, helped inspire the fictional setting of Morfa Halen.
That connection between people and their environment is central to the drama. The salt marsh itself becomes part of the atmosphere of the story, reinforcing the sense that the characters are living in a place shaped by the sea and vulnerable to its power.
Claire Oakley created the series
Under Salt Marsh was created, written and directed by Claire Oakley, whose previous work includes the 2019 film Make Up. She also directed episodes of Culprits.
The series was produced by Little Door Productions in association with Sky Studios. Claire Oakley serves as lead director, while Mary Nighy directed Episodes 3 and 4.
Oakley has said she wanted to avoid some familiar conventions of the police procedural. Rather than treating the crime simply as a mystery to be solved, she wanted the story to explore questions around protection, family and the environment.
The result is a crime drama in which the landscape is closely connected to the characters and the mystery unfolding around them.
How many episodes are there?
Under Salt Marsh consists of six episodes, each running for approximately 45 minutes.
The release schedule was:
- Episode 1: January 30, 2026
- Episode 2: January 30, 2026
- Episode 3: February 6, 2026
- Episode 4: February 13, 2026
- Episode 5: February 20, 2026
- Episode 6: February 27, 2026
The first two episodes premiered together on Sky Atlantic, followed by one new episode each Friday.
The full series is now available to watch on Sky Atlantic and NOW.
Where can you watch Under Salt Marsh?
Under Salt Marsh is a Sky Original and is available exclusively through Sky and NOW.
It is not available on Netflix, Prime Video or Disney+.
For viewers who prefer to stream the series, the complete six-episode run is available on demand through NOW.
Watch the official trailer
The official trailer sets up the central mystery: an isolated Welsh community, a devastating discovery and an approaching storm that could erase the evidence Jackie and Bull need to solve the case.
A crime drama built around more than the mystery
At first glance, Under Salt Marsh appears to have all the ingredients of a traditional murder mystery: an isolated community, a troubled detective, an unresolved case and residents with secrets to hide.
But the series also puts considerable emphasis on the people living inside that community and the environment surrounding them.
The storm provides an immediate sense of urgency, while Jackie’s personal history gives the investigation an emotional dimension. Her relationship with Bull is equally important, as the pair must work together despite the mistrust and unresolved history between them.
That combination of crime, character drama and an imposing Welsh landscape gives Under Salt Marsh its distinctive atmosphere.
For viewers drawn to tightly wound mysteries such as After the Flood and Broadchurch, the series offers another story in which a seemingly close community is forced to confront what has been hiding beneath the surface.
