Slow Horses Season 6 — MI5’s discarded spies become the targets

The agents banished to Slough House now face a threat to their lives. Slow Horses Season 6 follows Gary Oldman’s Jackson Lamb and his team as they go on the run and investigate who is hunting them. The six-part spy drama combines abrasive humor and institutional power struggles with a chase in which the spies have become the targets. Apple’s season announcement

Checked October 31, 2026 · South Korean availability

Covers the Season 6 premise and relationships revealed in official publicity, including some earlier-season background and a returning character. Does not reveal the Season 6 ending. Rated for adults in Korea; includes violence, killings and strong language.

Title: Slow Horses
Scope: Season 6 · Six episodes · British espionage drama
Release: September 16–October 21, 2026
Viewing: Apple TV · Korean subtitles · Adults only in Korea

The agents in the backwater office become targets

Slough House is the MI5 department where agents are sent after career-ending mistakes. Their boss, Jackson Lamb, is insulting and unpleasant but highly experienced in intelligence work. Distance from the polished headquarters does not keep his team out of espionage. Apple TV series synopsis

In Season 6, former Slough House agents begin dying, and two assassins work through a list of past and present members. The team must protect those still alive and discover who is targeting them. MI5 chief Diana Taverner is far from attentive to their safety. The Independent’s Season 6 introduction

Jack Lowden as River Cartwright (left) and Gary Oldman as Jackson Lamb · Official Season 6 still · © Apple TV · Published by Tom’s Guide · Image source

The key people at Slough House and MI5

Jackson Lamb · Gary Oldman

The head of Slough House insults his agents freely, but he is an experienced intelligence officer. He uses his field knowledge and information to confront MI5 headquarters. Character and cast source

River Cartwright · Jack Lowden

River is an agent at Slough House and one of Lamb’s subordinates. His enthusiasm can lead to mistakes; he and Lamb clash frequently while investigating together. Character and cast source

Kristin Scott Thomas and Gary Oldman · Official Season 6 still · © Apple TV · Image source

Diana Taverner · Kristin Scott Thomas

Taverner heads MI5. She is Lamb’s adversary within headquarters, and in Season 6 she draws the Slough House agents into a dangerous contest of retaliation and revenge. Character and cast source

Olivia Cooke as Sid Baker · Official Season 6 still · © Apple TV · Published by Tom’s Guide · Image source

Sid Baker · Olivia Cooke

Sid worked alongside River at Slough House in Season 1. She returns in Season 6, with Cooke’s comeback confirmed in Apple’s official trailer announcement. Character and cast source

A chase through bowling alleys and service stations

Director Adam Randall wanted to take the agents out of their familiar Slough House surroundings. He describes staging a chase through everyday British places such as bowling alleys and service stations, while connecting it to a complex espionage story. He also calls this a darker, heavier season, with more threats and deaths alongside the humor and characterization. James Hibbs’s director interview·Radio Times·September 15, 2026

Official Season 6 still · © Apple TV · Image source

The series adapts Mick Herron’s Slough House novels. Season 6 combines the sixth book, Joe Country, and the seventh, Slough House. Gaby Chiappe handled the adaptation, with Season 4 director Randall returning. Apple’s adaptation and production credits

All six episodes on Apple TV

Season 6 ran from September 16 to October 21, 2026, across six episodes. It is available on Apple TV in South Korea with Korean subtitles and requires a subscription. The Korean listing carries an adults-only rating. Official release schedule · Korean viewing page

On October 31, Apple TV’s Korean Top 10 series shelf displayed Slow Horses in first place. The official Apple TV Season 6 trailer below includes scenes beyond the opening premise. Apple TV’s Korean popular-series list

Official Apple TV Season 6 trailer

Praise for pace, reservations about familiarity and the chase

Tom’s Guide’s Malcolm McMillan finds the writing and rapid pacing polished despite a change in lead writer and the combination of two novels. He also praises Lamb and River’s rapport, the new cast members and Olivia Cooke’s return. September 8, 2026·Full-season review·Contains plot spoilers

The Independent’s Nick Hilton praises the photography, action and tension, but argues that repeatedly placing Slough House in danger and Lamb in conflict with headquarters has reduced the surprises. For him, its reliability also makes the next developments easier to anticipate. September 16, 2026·Season 6 review·Earlier-season and Season 6 spoilers

Writing in Korean on DVDPrime, individual viewer leat finds the flight from danger in Episodes 3–4 drawn out and some agents’ decisions unconvincing. The writer welcomes moments that bring out River’s personality, but considers the season weaker than its predecessors. Updated October 22, 2026·Personal full-season response·Ending spoilers in the original

If you’re looking for similar stories

Tehran · Apple TV — A Mossad hacker enters Tehran under a false identity and faces danger when her mission fails. It offers undercover espionage for viewers drawn to Slow Horses’ pursuit and escape, with the added pressure of maintaining a cover identity.

Sources and image credits

Photographs are official Apple TV publicity stills; some are reproduced from Tom’s Guide. Captions link to their sources. Images belong to Apple TV and the respective rights holders. Review originals contain Season 6 ending and earlier-season spoilers.

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