Paramount+’s Under Salt Marsh, the six-part psychological thriller that premiered September 25, 2025, has hurled viewers into a tidal wave of betrayal and buried sins, with Kelly Reilly commanding screens as DI Jackie Ellis, a “fallen detective” whose badge is battered by a single cold case that shatters her career, family, and fragile hold on sanity. Directed by The Missing‘s Kate Dolan and penned by Vigil‘s Meriel Baillou, the series – inspired by the 2019 novel Under the Salt Marsh by Lucy Ribchester – stars Reilly, 47, as the disgraced cop pulled from the depths to reunite with estranged partner DS Tom Carver (Rafe Spall, Jurassic World‘s chaotic charm curdled to brooding), unearthing a 15-year-old murder that drags them into a “deadly world of lies” where coastal creeks conceal corpses and loyalties. “It’s Mare of Easttown with a British bite – bigger, darker, more twisted than Broadchurch,” Baillou tells Radio Times, her script a scalpel slicing through Norfolk’s fogged fens, with Dolan cranking the claustrophobia from tide pools to therapy sessions. Filmed January-July 2025 in Norfolk’s briny bogs and shadowy suburbs, the “edge-of-your-seat” unspooling has spiked socials with 2.8 million #SaltMarshSecrets posts: “Slept worse after – pure paranoia!”

The saga’s sinister surge? Spellbinding: Episode 1’s “Tide of the Dead” catapults Jackie (Reilly, Yellowstone‘s Beth Dutton reborn as a badge-broken Beth) into the fray, a dredged skeleton from the salt marsh – a missing teen from 2010 – pulling her from demotion’s doldrums to DS Carver’s door, their “estranged” alliance a powder keg of past passions and present perils. Reilly’s Jackie? A “masterclass in menace,” her steely spine cracking under the creep of compulsion, unraveling a web where “secrets explode” into family fractures and false alibis. Spall’s Tom? A “vixen of vulnerability,” his rumpled resolve a reminder of their “buried” bond. Co-stars carve the chaos: Siobhan Finneran as the “suspicious sister” with a sting, Tom Glynn-Carney as the “haunted husband” with a grudge, and Indira Varma as the “calculating” colleague with secrets. Baillou’s quill quivers with quips – “The marsh keeps what it kills” – but the “brutal” brutality bites: A botched beach burial buries a body, a VVIP viper’s venom turns ally to assassin.

The “bigger than Mare”? Barbaric: Baillou’s adaptation amps the “pacy” probe with “spooky” soundscapes and “authentic” accents, Dolan’s direction a “gripping” gasp of “grim themes” in Norfolk’s “eerie charm.” The Guardian‘s Lucy Mangan raves “very well-made, pacy drama” with Reilly’s “reliably likeable” levity; The Independent‘s Ed Power hails Spall’s “Icily Glamorous” iciness and the “understated and spooky” score. Evening Standard‘s Vicky Jessop praises the “overall confidence, style and authenticity.” Skeptics? “Mired in darkness,” but the 1-in-2 clue-to-cliff ratio hooks, BARB metrics outgunning The Jetty.

This isn’t whodunit wallpaper; it’s a web-weaving whirlwind, Under Salt Marsh‘s salt marsh a testament to truth’s toll where secrets seep and sanity sinks. Jackie’s jeopardy? Jarring. Tom’s torment? Tormenting. September 25? Not a drop – a deluge. Binge it; the tides torment, the twists tantalize. Reilly’s resolve? Relentless. Spall’s shadow? Sinister. The obsession? Overnight, unquenchable.