British crime drama has never exactly been short of great mysteries.

From Happy Valley and Line of Duty to The Fall, Unforgotten, Luther and Broadchurch, viewers have spent years watching detectives pick apart crimes in communities where almost everyone appears to be hiding something.

But a newly released Welsh thriller is already drawing comparisons with some of the genre’s biggest successes — and one critic has gone as far as calling it “the best thing on TV right now.”

Under Salt Marsh stars Yellowstone’s Kelly Reilly alongside Rafe Spall and acting heavyweight Jonathan Pryce.

The atmospheric crime drama currently holds a perfect 100% Rotten Tomatoes rating, according to the source, with reviewers describing it as “as good as Broadchurch” and potentially one of the best British crime dramas in years.

And its central mystery begins with a horrifying discovery in the marshes.

A Body In The Marsh Reopens An Old Wound

Reilly plays Jackie Ellis, a former detective whose policing career ended after a devastating unresolved case.

She now works as a teacher in Morfa Halen, an isolated coastal village in north-west Wales where the sea is slowly becoming as threatening as any criminal.

Then Jackie discovers the body of a young boy in the surrounding wetlands.

The discovery is tragic enough on its own.

But for Jackie, it also drags another case violently back into the present.

Three years earlier, a young girl disappeared from the same community.

She was never found.

The investigation ultimately brought Jackie’s career as a detective to an end, leaving questions that have never gone away.

Now another child is dead.

And the possibility that the two cases could somehow be connected forces Jackie back toward a mystery she has spent years trying to live with.

Rafe Spall And Jonathan Pryce Join A Heavyweight Cast

Reilly is joined by Rafe Spall, known for The English, while Jonathan Pryce adds considerable dramatic weight to the ensemble.

Pryce’s extensive career includes The Crown, Game of Thrones, The Two Popes and Glengarry Glen Ross.

The combination gives Under Salt Marsh the kind of cast normally associated with a major prestige drama rather than a conventional detective procedural.

But the landscape is almost another character in its own right.

Morfa Halen may be fictional, yet the environmental danger surrounding the village is rooted in something very real.

The Village Is Fictional — The Threat Facing It Isn’t

The series unfolds against the haunting backdrop of a coastal community facing the possibility that it may eventually have to be abandoned because of rising sea levels.

Morfa Halen was inspired by the real Welsh village of Fairbourne.

Some scenes were actually filmed there, while the sweeping marshland seen throughout the drama was captured around the nearby Mawddach Estuary.

That real-world connection gives the fictional murder investigation another layer of tension.

This isn’t simply a community being shaken by the death of a child.

It is a community already facing the possibility of losing its entire future.

Homes, memories and generations of family history are tied to land that may eventually become impossible to protect.

Fairbourne Inspired The Drama’s Environmental Story

The crime at the centre of Under Salt Marsh is fictional.

The discovery of the boy’s body and the earlier disappearance of the girl are not presented as recreations of real cases.

The environmental storyline is different.

Fairbourne has faced years of uncertainty over its long-term future because of concerns about rising sea levels and coastal flooding.

According to the source article, residents were told in 2013 that they could potentially become the world’s first “climate refugees.”

At the time, plans indicated that sea defences would not continue to be maintained beyond 2054.

A strategy involving “managed retreat” was proposed, potentially requiring residents to relocate and eventually surrendering the community to the sea.

The plans sparked fierce resistance from residents.

The source also reports that officials may now be moving away from earlier proposals to “decommission” the village.

It is that sense of a community facing an uncertain existence that provides the backdrop for the fictional Morfa Halen.

Critics Are Already Making Broadchurch Comparisons

The combination of an isolated community, a dead child, buried secrets and an imposing coastal landscape has inevitably invited comparisons with Broadchurch.

The acclaimed ITV drama starring Olivia Colman and David Tennant ran between 2013 and 2017 and became one of Britain’s defining modern crime dramas.

Those comparisons aren’t only coming from viewers.

Writing in the Sydney Morning Herald, Craig Mathieson described Under Salt Marsh as “as good as Broadchurch.”

The Irish News offered an even stronger reaction, declaring it “the best thing on TV right now.”

Meanwhile, Vogue’s Daisy Jones argued that genuinely compelling British crime dramas can be surprisingly difficult to find despite the enormous number being produced.

She singled out Under Salt Marsh as one worth paying attention to, describing it as “one of the more gripping thrillers I’ve seen in years.”

More Than Another Murder Mystery

The setting helps distinguish the series from the endless procession of television police investigations.

There is a murder mystery to solve.

There is also the unresolved disappearance hanging over Jackie.

But beyond both is a community whose relationship with the landscape is changing.

The marshes are beautiful, isolated and ominous.

The sea is never simply scenery.

It represents another countdown running alongside the criminal investigation.

Even if Jackie can uncover what happened to the children, Morfa Halen still faces a much larger question about whether the community itself has a future.

That gives the drama two different forms of uncertainty: one created by human secrets and another by the environment surrounding them.

Kelly Reilly Trades Yellowstone For The Welsh Coast

For viewers familiar with Reilly as Beth Dutton in Yellowstone, Jackie Ellis offers a very different setting.

There are no sprawling Montana ranches here.

Instead, she is surrounded by marshland, water and the claustrophobia of a small community where the past refuses to remain buried.

Jackie is no longer a detective when the story begins.

But discovering the boy’s body makes keeping that former life at a distance increasingly difficult.

The old disappearance is still unresolved.

Her career was damaged by it.

And now another tragedy has occurred in the same village.

The question hanging over the drama isn’t merely who is responsible.

It is whether Jackie is finally going to discover the truth that escaped her three years earlier.

The Setting Makes Everything Feel More Isolated

The decision to film around Fairbourne and the Mawddach Estuary gives the series a distinctive visual identity.

Wide expanses of wetland surround characters who are already trapped by circumstances they cannot easily escape.

As the investigation deepens, that isolation becomes part of the tension.

Small communities can protect their own.

They can also preserve secrets.

And with Morfa Halen facing the possibility of eventually disappearing altogether, the pressure surrounding its residents becomes even more intense.

The village has a past it cannot resolve and a future it cannot guarantee.

Somewhere between those two uncertainties lies the mystery Jackie is forced to confront.

A New British Crime Drama Worth Watching Closely

Calling any new crime series the next Broadchurch sets an enormous expectation.

But Under Salt Marsh has arrived with the kind of early reception that makes those comparisons difficult to ignore.

A perfect Rotten Tomatoes score.

Kelly Reilly, Rafe Spall and Jonathan Pryce leading the cast.

A dead child discovered in a Welsh marsh.

Another child who vanished three years earlier.

And beneath the fictional mystery, the very real story of a coastal community fighting for its future.

For viewers who thought British television might have exhausted every possible variation on the small-town murder mystery, Under Salt Marsh has found a particularly haunting new setting for one.

And according to some of its earliest critics, it could be one of the strongest British crime dramas in years.

Under Salt Marsh is available to stream on NOW.