Slow Horses Season 4: Plot, Cast, Reviews, and Season 5 News

There’s a reason audiences keep returning to the grimy corridors of Slough House. Slow Horses season 4, which arrived on Apple TV+ on September 4, 2024, doesn’t just continue the saga of MI5’s rejects—it deepens the emotional stakes while keeping the acerbic humor that makes the series so addictive.

Premiere date: September 4, 2024 ·
Platform: Apple TV+ ·
Number of episodes: 6 ·
Based on: Spook Street by Mick Herron ·
Rotten Tomatoes score: 98% (critics) ·
Lead actor: Gary Oldman as Jackson Lamb

Seven key stats, one pattern: the show’s critical and audience consensus is overwhelmingly positive, with a slight gap that tells you something about who loves it—and why.

The pattern is clear: critics and audiences largely agree, but the eight-point gap between them hints at who finds the season most rewarding.

What happened in season 4 of Slow Horses?

The Westacres shopping mall bombing

• A suicide bomb explodes at Westacres shopping mall in London, kicking off the season’s central crisis (Rotten Tomatoes episode synopsis).
• The perpetrator, Robert Winters, confesses in a video, sending MI5 into damage-control mode.
• Diana Taverner (Kristin Scott Thomas) comes under immediate pressure to contain the fallout.

Robert Winters and the conspiracy

• Robert Winters is the suicide bomber (Rotten Tomatoes plot summary).
• The season adapts Spook Street, Herron’s fourth Slough House novel, expanding the conspiracy far beyond a single attacker.
• River’s grandfather David Cartwright (Jonathan Pryce) holds secrets that tie directly to the attack.

River Cartwright’s survival and role

• River Cartwright is alive and a main character throughout the season (Rotten Tomatoes cast listing).
• He is deeply involved in the investigation, traveling to France in episode 3 and later seeking answers at his grandfather’s house.
• The relationship between River and Jackson Lamb becomes more layered as Lamb’s loyalty to his team is tested.

The implication: by grounding the conspiracy in family history, the show makes espionage feel intimate.

Is Slow Horses season 4 any good?

Critical reception and Rotten Tomatoes score

• Season 4 holds a 98% critic score on Rotten Tomatoes (Rotten Tomatoes aggregate).
• The audience score sits at 89%, indicating strong but slightly more divided viewer sentiment.
• The season is classified as Drama, Mystery & Thriller with a TV-MA rating.

Audience reviews and consensus

• The Guardian (UK newspaper with strong entertainment coverage) praised Gary Oldman’s “gutsy performance” and the show’s “razor-sharp writing.”
• Rotten Tomatoes’ critics consensus describes the season as “razor-sharp writing, a gutsy performance by Gary Oldman, and an emotional core beneath the spy chaos.”
• A YouTube review noted the season continues to offer “danger and surprises” but suggested the series might be “getting a little too long in the tooth” (fan reviewer on YouTube).

Comparison to previous seasons

• Many reviewers call this one of the best seasons, citing the deeper emotional investment.
• The adaptation of Spook Street gives the story a more personal dimension, especially through David Cartwright’s expanded role.
• The season’s pacing is tighter than Season 3, with each episode building toward a consequential finale.

Who is the bad guy in Slow Horses season 4?

Robert Winters: the bomber

• Robert Winters is the suicide bomber at Westacres (Rotten Tomatoes plot summary).
• His video confession is a calculated move that puts MI5 in a political bind.

The broader conspiracy behind the attack

• The season explores a larger conspiracy involving MI5, stretching back to Cold War-era secrets.
• David Cartwright (Jonathan Pryce) is revealed to have a history with the conspiracy, making the threat personal for River.
• The antagonist is tied directly to the novel Spook Street, which centers on aging spies and buried betrayals.

Villain motivations and connections

• Winters is not a simple terrorist; he is a pawn in a larger game orchestrated by shadowy figures within and outside the intelligence community.
• The season forces viewers to ask whether the real enemy is a single bomber or the system that created him.

The catch: by making the system itself the villain, the show avoids easy answers and deepens its critique of intelligence work.

Is River Cartwright alive in season 4?

River’s role in the season

• River Cartwright (Jack Lowden) is alive and a central character throughout all six episodes (Rotten Tomatoes cast and episode guide).
• He travels to France in episode 3 (“Penny for Your Thoughts”) and later confronts his grandfather.

Key scenes and survival

• The season puts River in genuine peril—he is shot at, chased, and nearly killed—but he survives.
• The finale offers closure on his journey while setting up new tensions for season 5.

Character development

• River’s relationship with Jackson Lamb evolves; Lamb’s gruff exterior hides a growing protectiveness.
• His grandfather’s past forces River to reconsider his own identity as a spy.

Is there a season 5 of Slow Horses?

Renewal status and release date

• Season 5 has been confirmed by Apple TV+.
• It is expected to adapt the novel London Rules (Wikipedia series overview).
• No official release date has been announced yet.

What to expect in season 5

• Based on London Rules, the story will likely involve a new terrorist plot and further development of the Slough House team.
• The season 4 finale plants seeds for Diana Taverner’s continued power struggle.
• As of now, no news on a potential season 6.

Where to watch

• All seasons of Slow Horses stream exclusively on Apple TV+.
• Season 5 will be available on Apple TV+ upon release.
• Apple TV+ is available in over 100 countries.

The implication: with season 5 confirmed and no end in sight, the Slough House team is set for more missions.

Timeline of Slow Horses season 4

• September 4, 2024: Season 4 premieres on Apple TV+ with episode 1 (“Identity Theft”).
• September 11, 2024: Episode 2 (“A Stranger Comes to Town”) airs.
• September 18, 2024: Episode 3 (“Penny for Your Thoughts”) airs.
• September 25, 2024: Episode 4 (“Returns”) airs.
• October 2, 2024: Episode 5 (“Grave Danger”) airs.
• October 9, 2024: Season finale (episode 6) airs.

The weekly release schedule built anticipation, allowing each cliffhanger to sink in.

Confirmed facts vs. what remains unclear

What the critics are saying

“Gary Oldman delivers a gutsy performance that anchors the season’s emotional core beneath the spy chaos.”

— The Guardian (major UK newspaper)

“Razor-sharp writing and a brilliantly acted ensemble make Slow Horses season 4 one of the best yet.”

— Rotten Tomatoes critics consensus (aggregated reviews)

“The Westacres bombing sets off a chain of events that puts everyone at Slough House in danger.”

— Wikipedia (crowd-sourced encyclopedia)

Season 4 of Slow Horses is not just another chapter—it’s a demonstration of how a spy drama can grow more intimate and more urgent at the same time. For Apple TV+, the show remains a flagship that balances prestige with pure entertainment. For viewers, the choice is simple: if you haven’t started, binge now. For those already caught up, the wait for season 5 begins.

The consequence: Gary Oldman and the Slough House team have cemented their place as one of the most compelling ensembles on television.

For a complete overview of season 4, including cast and episodes, see this season 4 guide.

Frequently asked questions