Sky Atlantic’s latest original, Under Salt Marsh, has exploded onto screens as one of the standout British crime thrillers of 2026, earning a perfect 100% on Rotten Tomatoes and sparking fervent comparisons to the iconic Broadchurch. Premiering on January 30, 2026, with episodes rolling out weekly on Sky Atlantic and streaming on NOW, this six-part limited series has captivated audiences with its moody atmosphere, masterful slow-burn pacing, and unflinching exploration of grief, guilt, and environmental peril. Fans are calling it “the best thing I’ve watched in YEARS” and a “masterpiece,” praising its ability to deliver genuine shocks while weaving in deeper, timely themes.
Set in the fictional coastal village of Morfa Halen in north-west Wales—a name translating to “salt marsh” in Welsh—the story unfolds in a tight-knit community perched precariously between rugged mountains and an encroaching sea. The town faces constant threats from rising water levels and severe weather, creating a backdrop of existential dread that mirrors the personal turmoil of its residents. Filmed in stunning locations around Gwynedd and Anglesey, including Barmouth standing in for much of Morfa Halen, the series captures the wild, melancholic beauty of the Welsh coast: windswept marshes, dramatic cliffs, and stormy skies that feel almost alive with menace.
The narrative kicks off with a devastating discovery. Jackie Ellis (Kelly Reilly), a former detective now working as a primary school teacher, stumbles upon the body of one of her young pupils, eight-year-old Cefin Hill, in the marshlands while walking home one night. It appears to be a tragic drowning, but as Jackie examines the scene, doubts creep in. Haunted by her own past, she is drawn back into investigative mode despite having left the force years earlier.
Jackie’s history is deeply intertwined with the case. Three years prior, her nine-year-old niece Nessa vanished without a trace in the same area, a cold case that shattered Jackie’s career, her family relationships, and her sense of self. The unresolved disappearance led to her resignation from the police and a retreat into teaching, where she tries to rebuild a quieter life. Finding Cefin’s body reopens those old wounds, forcing Jackie to confront the guilt and trauma she has buried.
Complicating matters is the arrival of Detective Eric Bull (Rafe Spall), Jackie’s former partner and the man who worked alongside her on Nessa’s case. Eric is still tormented by the failure to solve that mystery, carrying the weight of professional regret and personal fallout. Their reunion is tense and fraught—estranged by blame, unspoken feelings, and the passage of time—but necessity binds them together. As a massive, once-in-a-generation storm gathers force offshore, threatening to obliterate evidence and potentially devastate the town, the clock ticks relentlessly. They must unravel the truth behind Cefin’s death before the waves wash everything away.
The series excels in its character-driven approach. Kelly Reilly delivers a powerhouse performance as Jackie—restrained yet intensely emotional, conveying layers of grief, determination, and quiet rage. Known for her commanding presence in Yellowstone, Reilly brings a grounded intensity to Jackie, making her both relatable and formidable. Rafe Spall matches her beat for beat as Eric, portraying a detective whose sharp mind is undermined by lingering self-doubt and the ghosts of past mistakes. Their chemistry crackles with history, turning every confrontation into a highlight.
The supporting cast adds rich depth. Jonathan Pryce appears as Solomon Bevan, a local farmer whose stoic demeanor hides complex ties to the community and the land. His character underscores the series’ environmental undercurrents, as the town debates coastal defenses while facing the harsh reality of climate change. Other key players include Harry Lawtey as Dylan Rees, a figure connected to the investigation’s web, and a ensemble of locals whose secrets gradually surface, revealing a community fractured by suspicion and long-held grudges.
Creator and executive producer Claire Oakley crafts a narrative that feels intimate and cinematic. The direction emphasizes the landscape as a character in its own right—the marshes are both beautiful and treacherous, symbolizing hidden dangers and the slow erosion of stability. Cinematography is exquisite, with sweeping shots of the Welsh coastline contrasting intimate, claustrophobic interiors. The impending storm builds tension masterfully, serving as a literal and metaphorical force that accelerates the plot while heightening emotional stakes.
What sets Under Salt Marsh apart from many contemporaries is its thoughtful integration of broader issues. Beyond the central mystery, the series explores climate anxiety and community displacement, drawing inspiration from real Welsh villages like Fairbourne that face similar existential threats from rising seas. It examines how environmental precarity amplifies personal and social fractures, turning a standard whodunit into something more resonant. The child victims’ stories add heartbreaking weight, delving into themes of loss, protection, and the failure of systems meant to safeguard the vulnerable.
Critics have been effusive. Reviews praise its careful plotting, psychological depth, and atmospheric mastery, often placing it alongside the first season of Broadchurch for its coastal setting, community focus, and emotional authenticity. One outlet called it “exceptional,” noting the “exquisite care” in its creation. Viewers echo this, flooding social media and review platforms with acclaim for the slow-burn suspense, powerful acting, and shocking twists that keep them guessing until the end.
Of course, not every element lands perfectly for all—some find the pacing deliberate to a fault, and a few have critiqued minor plot conveniences—but the overwhelming consensus is overwhelmingly positive. Trending high on streaming charts and sparking widespread discussion, Under Salt Marsh proves that even in a saturated genre, a well-crafted story with strong performances and meaningful themes can still shock and move audiences.
As the storm reaches its peak and secrets flood to the surface, Under Salt Marsh delivers a gripping, emotionally charged experience that lingers long after the credits roll. In a year of strong television, this Welsh thriller stands out as a haunting reminder of how fragile communities—and individuals—can be when nature and human darkness converge. If you’re seeking a crime drama that combines edge-of-your-seat suspense with genuine heart and relevance, this is it.
