Olivia Cooke Returns as Sid Baker in 'Slow Horses' Season 6 Trailer
The Apple TV+ spy thriller shocks fans with the return of a presumed-dead agent as Slough House goes on the run.
Apple TV+ has released the official trailer for Season 6 of 'Slow Horses,' confirming the surprise return of Olivia Cooke. The actress reprises her role as Sid Baker, a character who had been absent from the series for four seasons and was previously presumed dead.
The new footage reveals a chaotic shift in dynamics for the disgraced MI5 unit. Alongside Cooke's return, the trailer confirms that Rosalind Eleazar will return as Louisa. Having resigned from MI5 in the previous season, Louisa becomes a primary objective for the team, who must hunt her down to deliver a critical warning. The season's plot centers on the Slough House agents being forced on the run, caught in a high-stakes game of retaliation and revenge orchestrated by Diana Taverner.
The Slough House Legacy
'Slow Horses' is a British spy thriller adapted from the novels by Mick Herron. The series follows a collection of MI5 agents who have been exiled to Slough House—a dumping ground for those who have botched their careers—under the caustic leadership of Jackson Lamb, played by Gary Oldman. Since the early seasons, the fate of Sid Baker had remained a point of contention and mystery for the audience, leaving a narrative void that the series had yet to formally address.
Shifting Narrative Stakes
The return of Sid Baker represents a major pivot for the series. Because her character was believed to be dead, her reappearance introduces a new layer of mystery and emotional tension to the ensemble. This development, paired with the return of Louisa and the agents' status as fugitives, suggests that Season 6 is moving away from the episodic nature of internal MI5 politics and toward a more urgent, survival-focused thriller format. The shift places the agents in a position of extreme vulnerability, stripped of their official protections.
What to Watch
As the season unfolds, the primary focus will be on how Sid Baker's survival is explained and how her reintegration affects the group's fragile stability. While the trailer establishes the overarching conflict with Diana Taverner, the specific nature of the revenge game remains undisclosed. Viewers will be watching to see if the agents can navigate Taverner's traps while successfully locating Louisa before their enemies do.