Under Salt Marsh: Kelly Reilly and Rafe Spall star in 'gripping' new Sky Original drama about 'an unspeakable crime'

The atmospheric crime drama is set in a close-knit Welsh town
Helen Fear

Under Salt Marsh is an upcoming Sky Original crime drama which promises to be every bit as good as the hype. Trust us on this one.

There are crime dramas and then there’s THIS. Like Mare of Easttown, Happy Valley, and True Detective, Under Salt Marsh combines a killer plot, with a solid cast, and atmospheric locations.

Under Salt Marsh “blends atmospheric crime storytelling with a deeply human portrait of resilience and community”.

The streaming channel has now released first look pictures and a trailer for the “gripping” series. So here’s everything you need to know, including cast, start date, plot and number of episodes.

Rafe Spall and Kelly Reilly in Under Salt Marsh promo shot
Rafe Spall and Kelly Reilly joins forces in upcoming crime drama Under Salt Marsh (Credit: Sky)

What is the plot of Under Salt Marsh on Sky?

Under Salt Marsh centres on “an unspeakable crime” which takes place in a small Welsh community where everyone “trusts one another”. Well, at first, anyway.

The series begins as a “once-in-a-generation storm” rolls in from the sea. As the apocalyptic weather batters the community, former detective-turned-teacher Jackie Ellis makes a shocking discovery…

A synopsis tell us: “It reopens the wounds of a three-year-old cold case which cost her both her career and her family’s trust.”

Jackie is forced to reluctantly reunite with her estranged police partner Detective Eric Bull on “an investigation that will shake Morfa Halen to its core”.

We’re told: “Together, they must confront a community haunted by secrets and fractured by grief, before the incoming storm washes away the evidence forever.”

The residents of the small Welsh village are subsequently left wondering “who is capable” of committing such a shocking crime.

How many episodes is it?

The upcoming Sky Original drama will be six episodes long.

Claire Oakley created, wrote, and directed the series. She’s best known for working on the Molly Windsor film Make Up, and directing episodes of Culprits.

Jonathan Pryce as Solomon Bevan in Under Salt Marsh
The always brilliant Jonathan Pryce as Solomon Bevan in Under Salt Marsh (Credit: Sky)

Who is in the cast?

Kelly Reilly and Rafe Spall lead the cast in the Sky Original, Under Salt Marsh. And they are joined by a solid ensemble support.

Surrey-born actress Kelly, 48, stars as Jackie Ellis, the former detective who must solve the cold case to keep the trust of her neighbours. As well as an extensive career in films, she is perhaps best known for her portrayal of badass Beth Dutton in Yellowstone. She of many memes.

TV viewers will also know her as Kerra in Britannia, Jordan Semyon in True Detective, Dr Catherine Black in Black Box, and DI Anna Travis in Above Suspicion.

Rafe Spall, 42, plays Detective Eric Bull. The British actor is handy at both comedic and dramatic roles, just like his pa Timothy. Rafe is best known for playing Jason Ross in sitcom Trying, as well as Pete Griffiths in Pete Versus Life, and Reg Whitehead in Roadies.

The brilliant supporting cast includes Slow Horses’ Jonathan Pryce as prominent character

Also starring in the ensemble cast of Under Salt Marsh is:

  • DI Ray‘s Naomi Yang as
  • Clink’s Dinita Gohil.
  • The Guest‘s Kimberley Nixon.
  • Fool Me Once’s Dino Fetscher.
  • The Witcher: Blood Origin’s Lizzie Annis.
  • Death Valley‘s Rhodri Meilir.
  • Stella’s Julian Lewis Jones.

Where was Under Salt Marsh filmed?

The six-part drama is set in a close-knit Welsh town fractured by an unspeakable crime. The crime drama centres on the residents of fictional Welsh town Morfa Halen.

Cast and crew filmed in and around Wales, and the production received support from the Welsh Government via Creative Wales.

Industry's Harry Lawtey as Dylan Rees in Under Salt Marsh
Industry’s Harry Lawtey joins the ensemble cast as Dylan Rees (Credit: Sky)

When’s the start date? How can you watch it?

Under Salt Marsh will launch on Sky and streaming service NOW in 2026.

We’ll bring you more details as soon as we have them.

Read more: Love Shetland? 10 best Scottish crime dramas you must watch including ‘dark and twisted’ series compared to Luther

Under Salt Marsh will launch on Sky and streaming service NOW in 2026.