One of Apple TV’s best shows, “Slow Horses,” bounces back after a relatively down fifth season to deliver to fans what might be its best outing to date. More than anything, this adaptation of two Mick Herron books (Joe Country and Slough House) counters the current epidemic of streaming television wherein so many limited series feel like they should have just been a movie. How many times lately have you seen two hours of plot in an 8-episode box? It’s driving TV critics like yours truly slowly insane.
So seeing a 6-part series that zips by like a 90-minute action movie feels almost invigorating. There’s no 6-episode anything on television this year that hums like the sixth season of “Slow Horses,” an outing that’s entertaining, suspenseful, and honestly moving. After season five, I was a little concerned “Horses” was losing its cadence; now, I’m ready to watch it for another decade.
Of course, as is often the case with a season of “Slow Horses,” much of the joy is in how the complex plotting unfolds, so this review will be vague. It’s one of those shows in which it feels like the writers are always just a step ahead of the viewer, but it makes you sit forward to catch up instead of the common reaction to streaming originals of scrolling on your phone until something happens.
Since it’s really the inciting incident, it’s not a spoiler to say that the sixth season opens just after the death of David Cartwright, River’s (Jack Lowden) grandfather. As River deals with his grief, two potentially intertwined events upset the day he has to bury David. First, a pair of Russian assassins seem to be eliminating members of Slough House, and the fact that they’ve also been removed from the MI5 payroll speaks to a potentially high-ranking reason to do so. Second, the vicious Frank Harkness (Hugo Weaving) pops up, leading to a confrontation between him and River that also pushes through a season that wonderfully contains itself over a limited amount of time. In almost every episode, River has to explain he’s in a suit because he was at a funeral that day.
The previews have spoiled it, but the return of a thought-deceased former member of Slough House also defines the sixth season. Since it’s such a shock to the characters within the show, we’ll keep it secret, but suffice it to say that the subplot really gives the year emotional depth, not just in how it brings out a different side of Lowden but in its themes. The agents of Slough House were sent there because the powers that be saw them as disposable, but what happens when people who were kicked out of the house break back in? So much of “Slow Horses” has been about that idea: That sometimes all it takes to make a great spy is to evict them from the system that holds them back.
Much of this is reflected in Lowden’s work this year, the best of his career. While the show understandably has been pitched as a “Gary Oldman Vehicle,” and while the annual Emmy nominee is truly excellent, this season reminds viewers that it’s at least equally Lowden’s show. The potential next James Bond is put through the wringer physically and emotionally this year, almost to such a degree that one starts to consider if the entire arc of “Slow Horses” won’t be how a River Cartwright becomes a Jackson Lamb through constant betrayals, slain compatriots, and bad diets.
The writing on “Slow Horses” remains some of the strongest on TV, and it’s not just because of the thrilling plotting. As well as any spy fiction of this era can, the writers embed character in plot, using the former to drive the latter instead of pausing for awkwardly inserted backstory. One can feel history and a mix of both regret and pride in these people. There’s a scene between Weaving and Oldman at a Shake Shack, of all places, that’s a mini-masterpiece, one of the best of this year on any series. And kudos to Kristin Scott Thomas for once again taking a complex role and making it real. She has fully closed the deal on the idea that her Diana Taverner is the smartest person in most rooms, but maybe not always the most ethical.
As September and October turn up the dial on streaming originals with shows like “Crystal Lake” and “American Hostage” that are so anticipated that people are paying film festival prices to see them at TIFF (where “Slow Horses” is also dropping its first two episodes, for the record), “Slow Horses” stands out as the likely best of the crowded bunch.
Whole season screened for review. Premieres on Apple TV on September 16, 2026.
