Olivia Cooke returns as Sid Baker, the Slough House agent shot in the head back in season one, as Jackson Lamb tries to figure out who’s picking off his agents one by one.
Being connected to Slough House has never been safe on Slow Horses, and the new season six trailer makes that explicit from its first line: “Not everyone will make it out of Slough House alive.” Gary Oldman‘s Jackson Lamb spends the trailer trying to figure out why his current and former agents keep turning up dead, ambushing MI5 First Desk Diana Taverner, played by Kristin Scott Thomas, in her own garden to ask her directly. Her answer isn’t reassuring. “It’s a bloodbath,” Lamb concludes.
The team gets rounded up at a safe house and told to go dark, including Louisa (Rosalind Eleazar), pulled back in despite having tried to leave the service after her mental health break last season. “Stay dark,” Lamb tells them. “No phones.” Roddy, the group’s tech expert, ignores him within the same scene. Hugo Weaving‘s Frank Harkness, the estranged father of River Cartwright (Jack Lowden), also resurfaces, alongside a steady stream of explosions, shootouts, and hand-to-hand combat that suggests this season leans harder into action than usual.
Then the trailer’s real reveal lands. Lamb tells his assistant Catherine Standish, “We’re spies. We’ve all faked our own death at one time or another,” and the footage cuts to River coming face to face with Sid Baker, played by Olivia Cooke. Sid was shot in the head during a season one investigation and was presumed dead after time in intensive care, until Roddy discovered her MI5 records had been mysteriously erased, leaving the door open for exactly this kind of return. Apple confirmed Cooke’s comeback alongside the trailer’s release.
Apple describes the season this way: “Season six sees the Slow Horses on the run as Diana Taverner embroils them all in a fatally high-stakes game of retaliation and revenge.” The season adapts Joe Country and Slough House, the sixth and seventh novels in Mick Herron‘s Slough House series.
The full returning cast includes Oldman, Scott Thomas, Lowden, 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 as Peter Judd, Ruth Bradley as Emma Flyte, Tom Brooke as J.K. Coe, Jonathan Pryce as David Cartwright, and Hugo Weaving as Frank Harkness. BAFTA winner Lenny Rush joins as a new addition. James Callis, who played Whelan, does not appear to be returning.
Slow Horses has been Certified Fresh across all five of its previous seasons, with two of them landing perfect 100% scores on Rotten Tomatoes, and its most recent season pulled nine Emmy nominations including Best Drama Series. See-Saw Films produces for Apple TV, with Gaby Chiappe stepping in as showrunner this season, taking over from Will Smith, who ran the show for its first five seasons. Adam Randall returns to direct.
Season six premieres Wednesday, September 16, with new episodes releasing weekly through October 21.
