‘Slow Horses’ Season 6 Trailer: Olivia Cooke Is Back as the Slough House Faces a Deadly Hunt

Apple TV’s hit spy thriller Slow Horses is turning up the pressure in Season 6, with Gary Oldman’s Jackson Lamb warning his team to disappear as former Slough House operatives are targeted one by one.

The “Slow Horses” Season 6 trailer has arrived, and it wastes no time making one thing clear: nobody in Slough House is safe.

The Apple TV spy thriller returns on September 16, with Gary Oldman’s foul-mouthed intelligence boss Jackson Lamb forced to take his dysfunctional team underground after former members of the unit become targets in a brutal campaign of revenge.

But the biggest shock is saved for the end of the trailer: Olivia Cooke is returning as Sid Baker, the MI5 agent whose disappearance at the end of Season 1 left one of the show’s biggest mysteries unresolved.

Jackson Lamb Has a Body Count Problem

The Slow Horses Season 6 trailer opens with Jackson Lamb confronting MI5 power broker Diana Taverner, played by Kristin Scott Thomas, with an ominous question: why do his Slow Horses keep turning up dead?

The answer triggers a desperate scramble for survival.

Katherine Standish, played by Saskia Reeves, warns that anyone who has ever worked at Slough House could be in danger. Lamb’s blunt response? “It’s a blood bath.”

The official Season 6 storyline promises a particularly dangerous mission, with Taverner drawing the Slow Horses into what is described as a “fatally high-stakes game of retaliation and revenge.”

For a group already accustomed to bureaucratic humiliation, botched operations, and political games, the consequences this time appear far more permanent.

‘Stay Dark’ Lamb’s Team Goes Underground

Lamb quickly realizes that conventional spycraft won’t be enough.

In one tense exchange, he orders his team to disappear completely. “No phones,” he warns.

Then Roddy Ho, the group’s eccentric computer hacker, immediately calls him.

Lamb’s reaction perfectly captures the show’s trademark dark comedy even while their lives are potentially at risk; his colleagues remain spectacularly incapable of following instructions.

The trailer suggests the new season will combine the series’ familiar mix of espionage, gallows humor and dysfunctional teamwork with a much more dangerous survival storyline.

Former colleagues must be located and warned before whoever is targeting them can strike again.

Olivia Cooke’s Sid Baker Returns

Then comes the moment likely to dominate Slow Horses Season 6 discussions.

Olivia Cooke’s Sid Baker appears.

Sid was last seen in Season 1 and had effectively disappeared from the series’ central storyline. Her return is therefore a major development, particularly because the trailer shows her coming face-to-face with River Cartwright, played by Jack Lowden.

“Hello, River,” Sid says with a knowing smile.

River’s stunned reaction says almost everything.

Earlier, Lamb hints that Sid may not be the only person who has survived more than the team realized.

“We’re spies,” Lamb tells Standish. “We’ve all faked our own death at one time or another.”

That line could prove particularly important when the new season arrives.

Olivia Cooke’s Sid Baker Returns – Slow Horses Season 6

New Faces Join a Loaded Cast

The returning ensemble includes Christopher Chung, Aimee-Ffion Edwards, Rosalind Eleazar, Joanna Scanlan, Samuel West, Ruth Bradley, Jonathan Pryce and Hugo Weaving.

Lenny Rush, a BAFTA winner, is also joining the cast for Season 6.

The season is adapted from Mick Herron’s novels, with Gaby Chiappe serving as co-executive producer and Adam Randall directing.

See-Saw Films produces the series for Apple TV.

Season 6 Has a Lot to Live Up To

The new season follows an increasingly acclaimed run for “Slow Horses.” Season 5 received nine Primetime Emmy nominations, raising expectations for the next chapter of Lamb’s chaotic spy operation.

Season 6 will consist of six episodes, with new episodes arriving weekly through October 21.

With former spies being hunted, Slough House forced into hiding and Sid Baker suddenly back in River Cartwright’s life, the latest trailer suggests Apple TV’s most dysfunctional intelligence unit may be heading into its most dangerous mission yet.