Slow Horses season 4: next episode, recaps, cast, plot and everything we know about the Gary Oldman spy series

Gary Oldman in Slow Horses
Gary Oldman in Slow Horses (Image credit: Apple TV)

Quietly, Slow Horses has become one of Apple TV Plus' marquee TV shows, as the spy thriller that features plenty of wit is set to continue with Slow Horses season 4.

While Ted Lasso may have captured more attention, Slow Horses is already set to be one of the Apple TV Plus' longest-running original series to date, as in addition to season 4 the streamer has greenlit Slow Horses season 5, a number no other show has reached on Apple TV as of yet. So fair to say viewers have come to love Gary Oldman's Jackson Lamb (and his disheveled look) and his team of misfit spies that are called upon again and again to save the day.

So for all those who can’t wait for the next Slough House mission, here is everything you need to know about Slow Horses season 4.

Slow Horses season 4 next episode

Slow Horses season 4 episode 6 is now available to stream on Apple TV Plus.

All episodes of the spy drama are now available to stream. 

In order to watch the latest season of Slow Horses as soon as it comes out, you are going to need to be a subscriber to Apple TV Plus. If you become a subscriber ahead of the new season you can catch up with all three previous seasons of the spy series on the streaming service.

Slow Horses season 4 cast

Our beloved screwups are back for Slow Horses season 4. First off, Gary Oldman is set to reprise his role as Jackson Lamb, the brilliant but apathetic head of Slough House, one that has seen him receive nominations for Best Actor from BAFTA and the Golden Globes. Other members of Slough House returning for season 4 are Jack Lowden as River Cartwright, Saskia Reeves as Catherine Standish, Rosalind Eleazar as Louisa Guy, Christopher Chung as Roddy Ho, Aimee-Ffion Edwards as Shirley Dander and Kadiff Kirwan as Marcus Longridge.

Also set to reprise their roles from the first three seasons are Kristin Scott Thomas as Diana Taverner and Jonathan Pryce as David Cartwright.

Confirmed new members of the cast for Slow Horses season 4 include Hugo Weaving (The Matrix), Joanna Scanlan (Wicked Little Letters), Ruth Bradley (The Gold), Tom Brooke (Preacher) and James Callis (Blood & Treasure).

Slow Horses season 4 plot

Apple TV Plus has confirmed that Slow Horses season 4 is based on Spook Street, the fourth entry from Mick Herron's Slough House series. 

The official description of the season only offers that it opens "with a bombing that detonates personal secrets, rocking the already unstable foundations of Slough House." However, for a little more background, here is the synopsis of the book:

"What happens when an old spook loses his mind? Does the Service have a retirement home for those who know too many secrets but don’t remember they're secret? Or does someone take care of the senile spy for good?

"These are the paranoid concerns of David Cartwright, a Cold War–era operative and one-time head of MI5 who is sliding into dementia, and questions his grandson, River, must figure out answers to now that the spy who raised him has started to forget to wear pants. But River, himself an agent at Slough House, MI5's outpost for disgraced spies, has other things to worry about. A bomb has detonated in the middle of a busy shopping center and killed forty innocent civilians. The 'slow horses' of Slough House must figure out who is behind this act of terror before the situation escalates."

Slow Horses season 4 recaps

Here are the official synopses for the Slow Horses season 4 episodes release so far and our in-depth recaps for each:

Slow Horses season 4 episode 1, "Identity Theft"
"A London bombing puts Taverner under pressure. When River grows concerned for his grandfather, Louisa encourages him to go for a visit." Read WTW's Slow Horses season 4 episode 1 recap.

Slow Horses season 4 episode 2, "A Stranger Comes to Town"
"A naive agent makes a discovery about the Westacres bomber. Lamb suspects that David knows more than he’s letting on." Read WTW's Slow Horses season 4 episode 2 recap.

Slow Horses season 4 episode 3, "Penny for Your Thoughts"
"River is trapped in France. Back at Slough House, the Dogs have come for Lamb." Read WTW's Slow Horses season 4 episode 3 recap.

Slow Horses season 4 episode 4, "Returns"
"Taverner is desperate to hide dangerous secrets. River seeks answers at his grandfather's house." Read WTW's Slow Horses season 4 episode 4 recap.

Slow Horses season 4 episode 5, "Grave Danger"
"Lamb questions David about France as River comes face-to-face with the enemy." Read WTW's Slow Horses season 4 episode 5 recap.

Slow Horses season 4 episode 6, "Hello Goodbye"
"Season finale. Impossible decisions are faced and sacrifices are made." Read WTW's Slow Horses season 4 ending explained.

Slow Horses season 4 trailer

The Slow Horses season 4 trailer is here, revealing that Slough House appears to be the target of a dangerous assassin, though Lamb seems to be approaching it with his trademark nonchalant attitude. Watch the full trailer right here:

Slow Horses — Season 4 Official Trailer | Apple TV+ - YouTube Slow Horses — Season 4 Official Trailer | Apple TV+ - YouTube
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Michael Balderston

Michael Balderston is a DC-based entertainment and assistant managing editor for What to Watch, who has previously written about the TV and movies with TV Technology, Awards Circuit and regional publications. Spending most of his time watching new movies at the theater or classics on TCM, some of Michael's favorite movies include Casablanca, Moulin Rouge!, Silence of the Lambs, Children of Men, One Flew Over the Cuckoos Nest and Star Wars. On the TV side he enjoys Only Murders in the Building, Yellowstone, The Boys, Game of Thrones and is always up for a Seinfeld rerun. Follow on Letterboxd.