Slow Horses season 4: release date, cast, plot and everything we know about the Gary Oldman spy series

 Gary Oldman in Slow Horses.
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 it seems that viewers have come to love Gary Oldman's Jackson Lamb 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 release date

Slow Horses season 4 is set to premiere on Wednesday, September 4, on Apple TV Plus.

The first two episodes will be available to watch immediately, with new a single new episode then releasing every Wednesday until October 2. In case you're curious, that means there will be six episodes in the new season, which is right on par with past seasons.

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).

Image 1 of 7

Aimee-Ffion Edwards, Christopher Chung, Tom Brooke, Kadiff Kirwan and Rosalind Eleazar in Slow Horses
Aimee-Ffion Edwards, Christopher Chung, Tom Brooke, Kadiff Kirwan and Rosalind Eleazar in Slow Horses

Image 2 of 7

Jack Lowden in Slow Horses
Jack Lowden in Slow Horses

Image 3 of 7

James Callis and Kristin Scott Thomas in Slow Horses
James Callis and Kristin Scott Thomas in Slow Horses

Image 4 of 7

Jonathan Pryce in Slow Horses
Jonathan Pryce in Slow Horses

Image 5 of 7

Ruth Bradley in Slow Horses
Ruth Bradley in Slow Horses

Image 6 of 7

Hugo Weaving in Slow Horses
Hugo Weaving in Slow Horses

Image 7 of 7

Joanna Scanlan in Slow Horses
Joanna Scanlan in Slow Horses

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 that 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 trailer

Apple TV Plus hasn't made the Slow Horses season 4 trailer that was shown at the end of the season 3 finale available online, though some on the internet have posted it on YouTube and social media if you want to go and find it.