Slow Horses season 5: Apple TV Plus predicted release date, potential plot, and more news and rumors

Apple TV Plus’ gritty spy thriller, Slow Horses, has impressed viewers with its action-packed scenes, gripping drama, and incredible acting. It’s one of the longest-running Apple Originals and an Emmy-nominated TV show for good reason and there's more to come as Jackson Lamb and his Slough House team are set to return for season 5.

The fact that Slow Horses has so far managed to release a new season every year is a wildly impressive feat in today’s streaming landscape and they’re clearly not stopping anytime soon. Slow Horses season 4 has secured a 100% rating on Rotten Tomatoes and season 5 is already well on the way. Here’s everything we know about it so far from the Apple TV Plus release date, trailer, possible plot, and more news and rumors.

Potential spoilers follow for Slow Horses season 1-4. This is your fair warning.

Slow Horses season 5 release date prediction

Apple TV Plus renewed Slow Horses for a fifth season back in January 2024. And, in October, a X/Twitter post from FilmUpdates revealed that season 5 had already wrapped production, just ten months after renewal.

To back this up, during an interview with Collider in early October, showrunner Will Smith said: “We've nearly done Season 5. We've got a couple of days to finish off on it, but we're already into the edit, so it's coming. Don't worry, it's coming. Not as quick as you want, but it's coming.”

When asked when it would be out, Smith replied: “I genuinely don't know the answer as to when it's gonna be out, but I can't imagine that Apple would want to leave it longer than a year since Season 4. So, the latest it would be out, I would say, would be the same slot next year.” And Apple certainly haven't left it longer than a year so far.

Slow Horses has demonstrated an impressive release schedule, dropping a season every year since 2022 – and season 1 and 2 even came out in the same year. So, given that season 5 has wrapped production and was reportedly in edit in October, we’d make a release date prediction of mid-to-late 2025.

Slow Horses season 5 trailer

In what appears to be establishing itself as a Slow Horses tradition, there was a season 5 teaser trailer shared at the end of the season 4 finale.

In less than a minute, someone tries to kill Roddy, a terrorist plot threatens London, and once again, the police turn to Lamb to help them predict the next move. Plus, an unknown killing, although if Slow Horses’ history is anything to go by, it could be anyone – no cast member is safe. We’ll get into more about what the teaser trailer alludes to when it comes to plot below, and we'll update here as soon as we have a full trailer to share.

Slow Horses season 5 confirmed cast

Full spoilers follow for Slow Horses season 4.

Given who we saw in the season 5 teaser, here’s the confirmed cast for Slow Horses season 5:

• Gary Oldman as Jackson Lamb
• Jack Lowden as River Cartwright
• Kristin Scott Thomas as Diana Taverner
• Saskia Reeves as Catherine Standish
• Christopher Chung as Roddy Ho
• Aimee-Ffion Edwards as Shirley Dander
• Rosaline Eleazar as Louisa Guy
• Ruth Bradly as Emma Flyte
• James Callis as Claude Whelan
• Tom Brooke as J.K. Coe

While there wasn’t any sign of Joanna Scanlan (Moira Tregorian), Hugo Weaving (Frank Harkness), or Jonathan Pryce (David Cartwright), we’re not yet sure if they’ll be reprising their roles. Though Smith hinted at a highly possible return of Hugo Weaving, when speaking to Collider: “All I can say is that Hugo's character reappears in the books. That’s the only tantalizing glimpse I can give you of that.”

Slow Horses season 5 potential plot synopsis and rumors

Major spoilers follow for Slow Horses seasons 1-4.

Slow Horses season 5 is confirmed to be an adaptation of Mick Herron’s ‘London Rules’ novel, the sequel to ‘Spook Street’ which acted as the basis for season 4.

To get a strong look at the possible plot for season 5 then, here’s the book’s official synopsis: “Regent's Park's First Desk, Claude Whelan, is learning this the hard way. Tasked with protecting a beleaguered prime minister, he's facing attack from all directions himself: from the showboating MP who orchestrated the Brexit vote, and now has his sights set on Number Ten; from the showboat's wife, a tabloid columnist, who's crucifying Whelan in print; and especially from his own deputy, Lady Di Taverner, who's alert for Claude's every stumble. Meanwhile, the country's being rocked by an apparently random string of terror attacks, and someone's trying to kill Roddy Ho.

Over at Slough House, the crew are struggling with personal problems: repressed grief, various addictions, retail paralysis, and the nagging suspicion that their newest colleague is a psychopath. But collectively, they're about to rediscover their greatest strength - that of making a bad situation much, much worse. It's a good job Jackson Lamb knows the rules. Because those things aren't going to break themselves.”

From the season 5 trailer, we know that much of the show will stay true to the book. We also catch a glimpse of most of the main cast to confirm their return to Slough House, and there's an awkward kiss between River and Louisa that we're keen to unpack.

Following suit with the previous seasons, Slow Horses always runs for six episodes with the plot spanning the events of two or three days. It appears with season 5, they’ll be sticking to this tried-and-tested method, as Smith spoke to Collider: “You feel if you stretch it beyond that — I mean, you can invent — I worry it would feel like padding, and it would take you away from what is great about the books. So, six, I think, is the magic number.”

In season 4, River met his biological father, Jack (Hugo Weaving), which only looked to strengthen his relationship with Lamb. But what about more from Frank? Well, the man himself spoke to Forbes, further confirming a reappearance: "You probably know that Frank is in one of the other books, and so the assumption is at the end of this season, and certainly to anyone who had read the books, is that Frank will be coming back.”

He adds: "Frank gets to play his Get Out of Jail Free card, which he has had all along because he knows that MI5 and David Cartwright tried to set him up. He knows he's got that, so he can say that fabulous line, 'I'll get the next train.' He can be that sort of a character because he actually is a survivor and excellently slippery."

With the book synopsis and teaser trailer as a starting point, it's fair to say the core plot is etched out. But, for those who haven't read the books, and with the unique additions of the cast & crew, Slow Horses will undoubtedly bring twists and turns that we didn't see coming.

Will Slow Horses get more seasons on Apple TV Plus?

Slow Horses has already been renewed for season 6, so yes there’s most definitely more to come. As reported by Deadline, season 6 will be based on Mick Herron’s ‘Joe Country’ and ‘Slough House’ which are the sixth and seventh books in the series. Adding: “In season 6, the spies head out on the run as Diana Taverner embroils them all in a fatally high-stakes game of retaliation and revenge.”

While season 6 will take its plot from two novels, that leaves only one behind in the series. Though, according to Smith when speaking to Collider, Herron is working on book nine.

Furthermore, Smith adds that there’s interest from his perspective in a spin-off, “I do think, though, there’s a great book he wrote, the last book that came out, which is in the Slough House universe, and Slow Horses do come into it, which is called The Secret Hours. That could be a movie or a more limited number just because of the nature of that story.”

When asked about the potential for a Christmas special, Smith said: “Gary and Gisele [Schmidt], his wife, had a fantastic idea that I loved, which was to do a Slow Horses advent calendar where we did 25 little films, and you kind of went in each day like an advent calendar, but you could dot around the timeline.

So, you could maybe do one where Min was still alive, and you could just go in and have these little vignettes. I've also spoken to Gary about, “What do you think Lamb's Christmas is like, his actual Christmas Day? Where's he going?” We think he probably goes to the pub on his own. But that would be a great thing to do.” We didn’t have Slow Horses advent calendar on our 2024 bingo card, but we’re certainly here for it.

For more Apple TV Plus show-related coverage, read our guides on Ted Lasso season 4 and Severance season 2.