'Slow Horses' Season 4 Shuffles Up Early, Debuts in September 2024

Just when Apple TV+ seemed to have gotten into a groove, the little streaming service that no one watches other than critics decided to shake things up. The streaming service has a small group of reliable hits among its offerings (hits being an extremely relative term), with Slow Horses being the biggest British drama on the roster since it debuted in April 2022. In fact, Slow Horses was such a big hit for the streaming service that Apple TV+ streamed Season 2 all of nine months later in December and greenlit Seasons 3 and 4. However, after that double dose, Apple held Season 3 (which was long finished) for a whole year until December 2023. Fans assumed the same would be true for Season 4, especially when Season 5 was greenlit directly following Season 3's finale.

However, Apple TV+ is once again upending expectations with a surprise announcement that Season 4 will arrive in September 2024, along with the rest of the major fall debuts across its rivals. Whether this is a sign that Apple TV+ thinks Slow Horses can hold its own in a crowded field, a lack of having anything else ready to go due to the 2023 strike, or a need to get the series up and out because there's a better option for the holiday season is unclear.

This means that fans who have been eagerly waiting to see what's next for the residents of Slough House will not have nearly as long a wait as they thought. Also, Season 5, which will cover the events of writer Mark Herron's fifth novel in the series, London Rules, is already prepping for production. Maybe this also means that the series will become a regular fall event.

Here's the synopsis for Season 4:

Adapted from Spook Street, the fourth novel in the Mick Herron spy series, the darkly humorous drama follows a dysfunctional team of British intelligence agents who serve in a dumping ground department of MI5 known un-affectionately as Slough House. Jackson Lamb is the brilliant but irascible leader of the spies, who end up in Slough House due to their career-ending mistakes as they frequently find themselves blundering around the smoke and mirrors of the espionage world. Season 4 opens with a bombing that detonates personal secrets, rocking the already unstable foundations of Slough House.

Gary Oldman (Oppenheimer) once again stars as Jackson Lamb, with Jack Lowden (The Gold) as River Cartwright. The rest of the returning ensemble includes Kristin Scott Thomas (Gosford Park), Saskia Reeves (Roadkill), Rosalind Eleazar (The Personal History of David Copperfield), Christopher Chung (Waterloo Road), Aimee-Ffion Edwards (Wolf Hall), Kadiff Kirwan (My Policeman), and Jonathan Pryce (The Crown).

Season 4 brings a bevy of guest stars to the series, including Hugo Weaving (Patrick Melrose), Joanna Scanlan (The Larkins), Ruth Bradley (Guilt), Tom Brooke (Bodyguard), Leroy Kincaide (Gangs of London), and James Callis (Star Trek: Picard).

Will Smith (Veep) continues as the series showrunner and head writer, with Morwenna Banks (Funny Woman), Mark Denton (Medici), and Jonny Stockwood (iBoy) penning episodes. Director Adam Randall (I See You) helmed all six episodes for Season 4, taking over from Saul Metzstein (Doctor Who), who helmed all of Season 3. Smith also serves as executive producer alongside Jamie Laurenson, Hakan Kousetta, Iain Canning, Emile Sherman, Jane Robertson, Julian Stevens, Douglas Urbanski, Gail Mutrux, and Graham Yost. 

Slow Horses Season 4 will debut with two episodes on Wednesday, September 4, 2024, on Apple TV+ with two episodes, and then continue with new episodes streaming weekly on Wednesdays into October. Season 5 is already greenlit.