Slow Horses Season 6 Officially Retcons Apple TV's Show

Published Sep 28, 2026, 2:30 PM EDT Ben Sherlock is a Tomatometer-approved film and TV critic who runs the massively underrated YouTube channel I Got Touched at the Cinema. Before working at Screen Rant, Ben wrote for Game Rant, Taste of Cinema, Comic Book Resources, and BabbleTop. He's also an indie filmmaker, a standup comedian, and an alumnus of the School of Rock. Warning! Spoilers ahead for Slow Horses season 6. Ironically, for a show about redundant spies, Slow Horses is starting to feel a little redundant itself. Much like Jackson Lamb, it’s long past its prime, set in its ways, running on fumes, dependent on old tricks, and well overdue for retirement. Since it debuted in 2022, Slow Horses has been one of the most consistently thrilling action shows on television — and, surprisingly, one of the funniest shows on television — but there are only so many ways to cook this turkey, and season 6 may have finally reached the limit of the audience’s disbelief. It’s leaning on contrivances, like the return of River’s estranged dad, and the characters are starting to feel Flanderized. Season 6 is a two-book combo, concurrently adapting the novels Joe Country and Slough House, but the season’s central hook — two assassins checking off a kill list of former Slough House agents — just isn’t as compelling as past hooks, like a political assassination or the abduction of Catherine Standish. A list of agents is the oldest spy trope in the book. In its latest season, Slow Horses may have finally overegged the omelette. It’s getting a bit too far-fetched, a bit too repetitive, and a bit too simplistic. The season 6 premiere wasn’t as grabby as prior premieres, but the second episode, “Daddy Issues,” really took the cake. The episode significantly raises the stakes as Lamb figures out the Slow Horses are being systematically eliminated and orders his agents to go dark and regroup at Blake’s Grave. But River ignores the order and goes home instead, to locate the source of the mysterious calls that Roddy traced to River’s phone. He expects to find his dad, Frank Harkness, but instead finds his old colleague Sid Baker, who was presumed dead years ago. It’s Bobby Ewing all over again. Sid's Death Always Seemed Suspicious Via MovieStillsDB The supposed death of Sid Baker was one of the boldest, most shocking twists in television history. Game of Thrones killed off Ned Stark at the end of season 1, but Slow Horses killed off Sid in just the third episode. Sid was set up as River’s sidekick and comic foil, and she was played by Olivia Cooke, star of Ready Player One and House of the Dragon and Me and Earl and the Dying Girl — arguably the second-most recognizable main cast member after Gary Oldman — so she seemed like a prime candidate for a nice, shiny suit of plot armor. But at the end of season 1, episode 2, when River and Sid were just starting to warm up to each other, she took a bullet to the head. In episode 3, she was rushed to hospital in critical condition, and in episode 5, she was confirmed to have died. Slow Horses has a jaw-dropping twist in just about every episode — we found out that Lamb killed Charles Partner; River realized the apparent terrorist on the plane was a decoy; Roddy’s girlfriend turned out to be a honey trap (okay, maybe that last one wasn’t such a surprise) — but killing off Sid in just the second episode was the show’s gutsiest twist by far. That is, until it was undone by last week’s episode. As powerful as Sid’s death was, it always seemed suspicious. It was so abrupt, and Lamb barely seemed to care (he doesn’t care about much, but it does affect him when his own agents are in peril), and we never saw a body, so all signs pointed to a cover-up. It’s not all that surprising that Sid is still alive; it’s more surprising that Cooke found the time in her schedule, and managed to work her Slow Horses return around her travels to and from Westeros. Slow Horses Release Date April 1, 2022 Network Apple TV+ Cast Jack Lowden River Cartwright Showrunner Douglas Urbanski