Slow Horses Season 6 Premiere: A Killer Targets Slough House’s Forgotten Spies in ‘Circle of Life

Apple TV+ returned its critically acclaimed spy drama Slow Horses with the premiere episode “Circle of Life,” which is now streaming as it sets up a chilling new mystery. Written by Gaby Chiappe and directed for television, the six-episode sixth season adapts two of Mick Herron’s Slough House novels rather than one, marking the first time since creator Will Smith departed that the series has been led by another hand. The episode establishes its central puzzle almost immediately: an unidentified pair is methodically eliminating former MI5 operatives who have retired to ordinary lives, while the current roster of Slow Horses misfits finds itself erased from every system at the Park.

The opening moves move quickly and without apology. Two agents who had stepped away from intelligence work are found dead by a shadowy twosome, played by Andor’s Kyle Soller and The Witcher’s MyAnna Buring. Simultaneously, the Slow Horses file is wiped clean across the agency’s networks, their paychecks vanishing along with their records. In response, the greasy, day-drinking chief Jackson Lamb (Gary Oldman) declares a “strike,” which in practice means retreating to the Italian restaurant beneath Slough House and uncorking a bottle of red wine before noon. The move is as much a protest as it is a character study in calculated inaction.

A New Voice at the Pen

The most pressing question surrounding this season was whether Slow Horses could survive without Will Smith, whose background on comedies like The Thick of It and Veep gave the series its distinctive, caustic edge. Gaby Chiappe, a longtime co-executive producer now serving as head writer, carries the show forward with a slightly different sensibility. The result remains unmistakably twisted—Lamb still burps loudly and laughs at funerals—but reviewers have noted that the new regime occasionally seems to lean on familiar character tics rather than trusting its own storytelling.

“It’s hard to be too nitpicky with a series that cranks out new seasons like clockwork and reliably hits its marks. Even so, it’s maybe trying a little too hard to prove that it knows how the show’s schtick is supposed to go.”

[Reviewer commentary on Slow Horses Season 6]

The tonal balance holds up even when the gags land. One of the season’s most poignant sequences follows River Cartwright (Jack Lowden) as he grapples with the off-camera death of his grandfather David (Jonathan Pryce). The show juxtaposes this quiet, sentimental farewell against Lamb’s crude antics, a deliberate contrast that underscores the series’ range. Even in mourning, River finds an odd outlet, delivering a eulogy that praises David’s love of railway systems as a thinly veiled cover for his years of espionage work.

The Chessboard Is Set

Beneath the dark comedy lies a dense web of interconnected clues. Diana Taverner (Kristin Scott Thomas), now firmly installed as First Chair after outmaneuvering the bumbling Claude Whelan at the close of Season 5, appears to have orchestrated Slough House’s digital erasure without openly admitting responsibility. Meanwhile, River confronts lingering grief while navigating his own uncertain standing within the agency.

The episode plants a surprising number of threads for what remains of its abbreviated run. A raid on a Russian finance botfarm, the identity of the spy-killers, River’s estranged father Frank Harkness (Hugo Weaving), and secret money funneled by the slimy politician Peter Judd (Samuel West) all surface as potential pieces of a larger puzzle. As arguably the most consistent spy series on television today, Slow Horses has always favored the less obvious twist, suggesting that these elements will not coalesce as neatly as they first appear.

Looking Ahead

With only five episodes remaining after the premiere and two books’ worth of source material to compress, the season faces a demanding schedule. Reviewers have already begun speculating about which established characters might return before the finale, with fans eager for news of familiar faces resurfacing on screen.

The sixth season confirms its longevity even as it navigates a transition behind the scenes. Slow Horses remains tonally consistent and reliably sharp, setting up its central mystery—someone is picking off Slough House spies, and no one at the Park seems willing to intervene—with plenty of clues left for viewers to chase. Whether Chiappe’s vision can sustain that momentum across the remaining episodes will determine whether this season joins the ranks of its predecessors as a standout entry in the series.