Summary

• Slow Horses is packed with great episodes throughout its three seasons.
• The show succeeds largely thanks to its mix of character development and thrilling action.
• While no Slow Horses episodes are total dude, some are more successful than others.

Warning: Contains MAJOR SPOILERS for Slow Horses, seasons 1, 2, and 3Since its debut in 2022, best spy-thrillers on TV, with all 18 episodes receiving plaudits. Given the consistent quality and pace of the storytelling, ranking all Slow Horses episodes is far less straightforward than it is for other series that might suffer a dip from season to season. Nevertheless, while every Slow Horses episode has its merits, some still stand up better than others.

Each season of Slow Horses tells a self-contained story based on one of Mick Herron's Slough House book series. Season 1 introduces the eponymous team based in a neglected branch of MI5, whose have variously disgraced themselves in the line of duty. Over three seasons, the team finds themselves embroiled in several high-level plots, including a white nationalist kidnap scheme gone wrong (season 1), a clandestine network of Russian sleeper agents (season 2), and a rogue ops team determined to expose government secrets (season 3). Each story contains stand-out moments, all contributing to Slow Horses' success.

18 "Last Stop"

Season 2, Episode 1

Despite being the lowest-ranked Slow Horses episode, "Last Stop" is still a hugely entertaining introduction to the show's sophomore season. Setting up many of the story's major plot points, the episode opens with a riveting sequence during which Dickie Bow pursues a mysterious man on a train, only to mysteriously die of a heart attack hours later. Jackson Lamb's investigation into his death sets the whole narrative in motion, leading to season 2's nail-biting climax. However, the episode inevitably suffers from having to set up the stakes and major players, impacting the overall pace.

17 "From Upshott With Love"

Season 2, Episode 2

Although Slow Horses season 2 concludes in thrilling style, the season's more complicated story of Russian sleeper agents and secret back channel meetings between MI5 and Russian leadership hopefuls does make it more convoluted than season 1's streamlined approach. In the end, the story more than pays off. However, much like season 2, episode 1, "From Upshott With Love" slightly suffers from having to set up so many story strands. River's mission in the Cotswolds, Lamb's investigation, and Min and Harper's side mission all get substantial screen time, and many threads only pay off in later episodes.

16 "Work Drinks"

Season 1, Episode 2

Much of Slow Horses' success stems from its characters. Despite lacking some of the action of later episodes, season 1's "Work Drinks" adds even more depth and color to the cast after the promising set-up of episode 1. The show's second-ever episode establishes Taverner's duplicity, makes Min and Louisa immediately sympathetic, and highlights River's simultaneous naivety and sense of honor. All of this not only makes the Slow Horses season 1 ending more impactful, but sets the characters up for their individual arcs as the show progresses.

15 "Failure's Contagious"

Season 1, Episode 1

Much like "Work Drinks", "Failure's Contagious" is a masterclass in character development. Following a gripping opening sequence set in Stansted Airport, the episode not only brings to life the claustrophobic confines of Slough House, but also introduces the inimitable Jackson Lamb, instantly establishing him as a character for the ages. Although the episode is mainly dedicated to set up, moments like River's failed training op and the dramatic revelation that a terrorist kidnap plot is underway make season 1, episode 1 a great taste of what's to come throughout the rest of the series.

14 "Drinking Games"

Season 2, Episode 3

One of Slow Horses' greatest strengths is its ability to shock the audience with unexpected twists and character deaths. "Drinking Games" delivers on both these fronts. While River's first steps investigating the cicada mystery are a little low-key, the episode more than makes up for it with Min's shocking death and River's tense dinner with a killer. Like other early season 2 episodes, episode 3 still has to contend with multiple narrative strands. However, by this point in the story, things begin to pull together in a way that can't help but reel a viewer in.

13 "Strange Games"

Season 3, Episode 1

Unlike previous opening episodes, Slow Horses season 3, episode 1 doesn't have to do much by way of character development, since the major Slough House players are already established. Instead, "Strange Games" features a thrilling opening sequence set in Istanbul, which ends in a murder that quickly establishes the stakes for the entire season. The episode's ending, involving a kidnapped Standish being threatened with a gun, also means that season 3 has a much faster pace from the off than previous installments – setting the tone for what follows.

12 "Visiting Hours"

Season 1, Episode 4

After the set-up of earlier episodes, season 1, episodes 3 and 4 are where Slow Horses comes into its own as a break-neck thriller. After the revelations of episode 3, "Visiting Hours" continues the action, with of Slough House forced to go on the run and evade MI5's operational team, "the dogs". The frenetic pace and confusion of the episode feels surprisingly authentic as events quickly spiral out of control. Unlike other entries in the spy subgenre, the protagonists always seem on the back foot with very little chance of escape. This tension only adds to the show's drama.

11 "Cicada"

Season 2, Episode 4

In contrast to the comparatively sedate pace of the first three episodes, "Cicada" ramps up the Slow Horses season 2 action with a series of stunning revelations. First, Lamb confirms that Harper was murdered by the man River has just had dinner with. Then, Lamb discovers that Katinsky has been operating as a triple agent, before he and Dander discover that Nevsky has shot himself after being poisoned with radiation. Finally, River apprehends Katinsky and Nevsky at the Upshott flying club, only to be incapacitated by Alex Tropper – the real sleeper agent. All of this makes "Cicada" a gripping watch from beginning to end.

10 "Bad Tradecraft"

Season 1, Episode 3

Part of the pleasure of Slow Horses' complex storytelling is discovering what is actually going on behind the scenes at the same time as the characters. Season 1, episode 3 demonstrates this trick to perfection. In a meeting between Lamb and Taverner, it's revealed for the first time that the entire kidnap plot is actually a false flag designed to gain favor with the Pakistani government. As if this development wasn't surprising enough, the episode ends on a genuine cliffhanger, when Lamb, River, Louisa, and Min discover the beheaded corpse of Taverner's mole, indicating something's gone terribly wrong.

9 "Negotiating With Tigers"

Season 3, Episode 3

Like other successful episodes of Slow Horses, "Negotiating With Tigers" works because it manages to expertly subvert expectations. Initially, order seems to have been restored after the revelation that Standish's kidnappers are actually a "tiger team" designed to test MI5 security. However, things almost immediately unravel when the team reveals their true intentions, abandoning the parameters of their mission. This, in turn, leads to the shocking death of James Webb – a moment that genuinely comes out of nowhere after his survival in season 2.