“Slow Horses” Season 4 is officially done because, well… of course it is. The show has been a critical success for Apple TV Plus and famously each season ends with a trailer for the next season.
Season 3 was no different. The third season of this British spy thriller was incredible: it was the best TV show I saw in 2023, and as is tradition, we got a preview of season 4 at the end of the sixth and final episode of the season.
Thanks to this trailer, we already know quite a bit about the next season of the show. And we know we’ll see a trailer for season 5 after the final episode of season 4, since Apple has already greenlit a fifth season.
Here’s everything we know about “Slow Horses” season 4, including the show’s release date, cast, trailers, and more.
Release date for the fourth season of ‘Slow Horses’ and where to watch it
Despite having a trailer for season 4, we don’t really know when the next season of “Slow Horses” will arrive on Apple TV Plus. But showrunner Will Smith (no, no that Will Smith) said in an interview with Decider that the first episode will definitely arrive on the streaming service before the end of 2024.
We expect “Slow Horses” to launch on Apple TV Plus in late November 2024. The final season arrived on Wednesday, November 29, 2023, and the previous season arrived on Friday, December 2, 2022. If I had to guess an exact date for season 4, I would choose Wednesday, November 27, 2024, with the first two episodes will be released that day and the Season 4 finale will arrive on Apple TV Plus on Wednesday, December 25. Talk about an amazing Christmas gift.
Spoiler alert: Spoilers for “Slow Horses” seasons 1-4 beyond this point
Cast of the fourth season of ‘Slow Horses’
Despite a now-familiar cast, the show’s main cast is a surprisingly small group. Gary Oldman’s Jackson Lamb, Jack Lowden’s River Cartwright and Kristin Scott Thomas’ Diana Taverner are the only main cast members of “Slow Horses.”
However, thanks to the new trailer and some casting announcements We can make an educated guess about who to expect in season 4. Here’s the full cast we know so far:
- Gary Oldman as Jackson Lambthe failed spy in charge of Slough House, also known as the “Slow Horses”
- Kristin Scott Thomas as Diana Tavernerthe former deputy director and now (alleged) head of MI5 who has a long history with Lamb.
- Jack Lowden as River Cartwrightone of Lamb’s “slow horses”, who is a relatively competent MI5 agent and was raised by his grandfather, who was a former MI5 legend.
- Saskia Reeves as Catherine StandishLamb’s secretary and recovering alcoholic who apparently leaves Slough House at the end of season 3.
- Rosalind Eleazar as Louisa Guyone of Lamb’s “slow horses” who is dealing with the trauma of a past relationship with a coworker.
- Christopher Chung as Roddy Hoa member of Slough House who is tech-savvy and incredibly annoying.
- Aimee-Ffion Edwards as Shirley Dander, one of Lamb’s “slow horses” who has anger issues and a bit of a drug addiction.
- Kadiff Kirwan as Marcus Longridge one of Lamb’s “slow horses” who has a serious gambling problem.
- Jonathan Pryce as David CartwrightRiver’s grandfather who was an MI5 legend but who is little by little losing his mind.
- Hugo Weaving as Frank Harknessprobably the main antagonist of season 4.
- Ruth Bradley as Emma Flyteapparently a newly introduced member of MI5.
- James Callis as Claude Whelan, apparently Taverner’s new second-in-command at MI5.
- Joanna Scanlan, in a currently unknown role
Trailers for the fourth season of ‘Slow Horses’
Apple has yet to release an official trailer on YouTube, but luckily an intrepid soul uploaded it for us. You can watch it below, although we’re heading into spoiler territory from here on out.
The first trailer for Season 4, which we see at the end of Season 3, shows Jackson Lamb in a miserable state, although he wouldn’t tell you that. Meanwhile, a bomb has exploded in London and MI5 is in ruins. Emma Flyte (Ruth Bradley), appears as a new member of MI5 and is now apparently a liaison between Slough House and MI5. MI5 is now run by Diana Taverner, and is using Flyte to inquire about the status of Lamb’s “rejects”.
And then there’s River Cartwright, who, unsurprisingly, is now caught in another dangerous situation facing a menacing Frank Harkness (Hugo Weaving) who wants River to join him or die. As if that weren’t bad enough, he’s also dealing with his grandfather’s (Jonathan Pryce) deteriorating health.
If this Season 4 trailer is any indication, we can expect the same wonderful blend of tension, action, wit, and charm that makes “Slow Horses” so great.
Plot of the fourth season of ‘Slow Horses’
The fourth season of “Slow Horses” has been confirmed to be an adaptation of Mick Herron’s 2017 novel “Spook Street,” the fourth novel in his Slough House series. I’m not going to go into spoilers here: if you want to know everything that could happen, do a little spy work and read the book yourself.
However, I will give you a brief synopsis of what to expect, and that will include some spoilers for the last three seasons, as well as possible spoilers for season 4.
In season 3, we begin to see Jonathan Pyrce’s David Cartwright (River’s grandfather) begin to show early and worrying signs of dementia. Unfortunately, those worries are real, and in “Spook Street” River must deal with his grandfather’s deteriorating mental state while also dealing with a bombing that has killed dozens of civilians. Season 4 will certainly be complicated and will not pull any punches. It will also be the last time we see a certain cast member: at the end of the Season 4 trailer, Gary Oldman’s Jackson Lamb announces that one of his crew has died.
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