Slow Horses Season 6 Episode 3, titled “Resurrection,” delivered the moment fans have waited since 2022: River Cartwright (Jack Lowden) and Sid Baker (Olivia Cooke) sharing the screen again. The episode premiered on Apple TV on September 30, 2026, and picked up exactly where Episode 2 ended — with River discovering Sid, alive and well, inside his late grandfather’s house.
- Episode title: “Resurrection”
- Release date: September 30, 2026 on Apple TV
- Where to watch: Apple TV (global — USA, UK, Canada, Australia, India, and worldwide)
- Season format: 6 episodes, weekly through October 21, 2026
- New episodes drop: Every Wednesday
- Key cast: Gary Oldman, Jack Lowden, Olivia Cooke, Kristin Scott Thomas, Saskia Reeves, Christopher Chung, Rosalind Eleazar, Joanna Scanlan, Hugo Weaving
What Happened in Slow Horses Season 6 Episode 3
The hour opens at David Cartwright’s house, right where the previous episode stopped. River stumbles across Sid instead of his mercenary father, Frank Harkness (Hugo Weaving). Their banter is sharp and awkward — Sid seems almost casual, while River is still processing three years of grief.
That tension barely has time to breathe. Two assassins — Jim and Jane, played by Kyle Soller and MyAnna Buring — pull up the long driveway, and Sid immediately recognizes them. She tells River they are there to kill her. What follows is an episode-long cat-and-mouse chase through fields, cattle sheds, and an elderly woman’s home, with River and Sid barely staying ahead of their pursuers.
The assassins appear to have been looking for River too. According to Forbes critic Erik Kain, Sid looks like “one name among many” rather than the sole reason the Slough House files were wiped.
“Sid’s return … it adds something very, very different to the show. I think the show doesn’t really do romance in a way, and I think it just brings a huge beating heart to this season, especially a season where there’s a lot of darkness.”
— Adam Randall, Slow Horses director, speaking to Radio Times
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Why Was Sid Baker’s Death Faked for Three Years
Sid survived getting shot — that part was real. A piece of the bullet is still lodged in her head, and she has named it “Poirot” because it occasionally “talks” to her. After recovering in a London hospital, Diana Taverner (Kristin Scott Thomas) arranged for Sid to be moved to an English village, where she spent three years recuperating and remaining out of sight.
The reason ties back to an MI5 mess: Moody, an MI5 operative doing Taverner’s dirty work, had shot Sid. Letting her survival become public knowledge could have opened an inconvenient investigation for the agency. Her death was allowed to become the accepted story, and Sid vanished from her former colleagues’ lives — all without her own knowledge that Taverner had wiped her records from existence.
River’s first reaction is relief mixed with anger. He spent three years carrying guilt over her supposed death, while she never contacted him once. Sid points out the awkwardness of him centering his own trauma above hers, but the guilt and responsibility of that loss has clearly weighed heavily on River since the show’s start.
The Russian Connection and the Kazan Killings
Sid has another reason to believe someone wants her dead. Weeks before the episode’s events, she received a travel order to the Russian city of Kazan. Her handler later dismissed it as a system glitch — but assassins began searching her village soon afterward.
While fleeing with River, Sid discovers that a woman was murdered in Kazan in what was reported as a botched robbery. Two gunshots to the head hardly scream petty theft, though. River develops a theory: someone may have used Sid’s identity for the Kazan operation and generated travel records to make it appear the real Sid carried it out. His suspicion falls on Taverner — though there is no confirmation yet that she engineered the travel order or the killing.
The Russian connection has firmer footing. During the chase, Jane slips into Russian before Jim reprimands her for speaking the language. Sid still trusts Taverner enough to call her from a payphone despite warnings that Regent’s Park may be compromised. After three years of being hidden by MI5, that faith could prove either remarkably perceptive or spectacularly misplaced.
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Moira Tregorian Survives as Blake’s Grave Protocol Activates
Sid isn’t the only resurrection in “Resurrection.” Moira Tregorian (Joanna Scanlan), who was left for dead by Jim and Jane in Episode 2, is rescued just in time. Shirley Dander (Aimee-Ffion Edwards), Catherine Standish (Saskia Reeves), and Louisa Guy (Rosalind Eleazar) discover a gas leak at Moira’s house and drag her from the poisoned home before it kills her.
The rescue happens because the Blake’s Grave protocol — a pre-arranged emergency meeting signal — was activated after the Slough House agents learned they were being targeted. Louisa is pulled out of a corporate boardroom meeting after being told her uncle Blake is in grave condition, a neat piece of misdirection and a reminder of how the team communicates under pressure.
Meanwhile, Jackson Lamb (Gary Oldman) and Roddy Ho (Christopher Chung) track down Reece Nesmith, the son of a former Dog of the Park. Reece gives Lamb his dead father’s phone and reveals that files were stolen from the Park on Frank Harkness’s orders. Lamb uses this to confront Diana Taverner directly — telling her the Slough House agents’ deaths are not coincidence, and that their physical and digital records were erased from the Park’s servers. He leaves after suggesting the operation is likely revenge for something Diana did.
Slow Horses Season 6 Cast and Where to Watch
The full returning cast for Season 6 includes Gary Oldman as Jackson Lamb, Jack Lowden as River Cartwright, Olivia Cooke as Sid Baker, Kristin Scott Thomas as Diana Taverner, Saskia Reeves as Catherine Standish, Christopher Chung as Roddy Ho, Aimee-Ffion Edwards as Shirley Dander, Rosalind Eleazar as Louisa Guy, Joanna Scanlan as Moira Tregorian, Samuel West, Ruth Bradley, Tom Brooke, Jonathan Pryce, and Hugo Weaving. BAFTA TV award winner Lenny Rush joins the cast this season.
All six episodes of Slow Horses Season 6 stream on Apple TV globally, with new episodes released weekly on Wednesdays through the finale on October 21, 2026. The series is available in the USA, UK, Canada, Australia, India, and worldwide wherever Apple TV operates.
What Olivia Cooke and the Director Said About Sid’s Return
Olivia Cooke filmed her Season 6 scenes during five weeks of night shoots before Christmas, after wrapping another project. She told Elle in August 2026 that she had always heard “murmurings” about her return but it was never guaranteed: “I was biding my time”.
Director Adam Randall said the reveal was originally meant to be a bigger surprise. “We obviously build up this whole idea that, ‘Where’s Frank? Frank’s calling him. Frank’s in the house.’ And then the surprise that it’s her,” Randall told Radio Times. He added that he did not know the trailer would reveal Sid until he saw the first cut of it.
Randall also teased a possible romantic arc between River and Sid. “I think it just adds something very, very different to the show,” he said. “It brings a huge beating heart to this season, especially a season where there’s a lot of darkness”.
Season 6 Adapts Two Mick Herron Novels
Slow Horses Season 6 is the first to combine two books from Mick Herron’s Slough House series — “Joe Country” (2019) and “Slough House” (2021). Gaby Chiappe took over as showrunner from Will Smith, who stepped down after five seasons. Chiappe told TV Insider that combining the two novels “made complete sense,” and warned that “when they’re in danger, the danger is very, very real, and sometimes people die”.
Season 6 also sits at a 100% critic score on Rotten Tomatoes based on early reviews, continuing the show’s record of never dipping below 95% across any season. The audience score debuted at 91%, a new all-time record for the series.
Also Read: Slow Horses Season 6 Premiere Delivers Sneaky Mick Herron Cameo During Funeral Scene
Slow Horses continues to prove why it remains one of Apple TV’s most reliable dramas, and Episode 3 just raised the stakes in every direction.
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