Olivia Cooke has returned to Apple TV's hit British spy thriller Slow Horses, reprising her role as Sid Baker in season six despite her character being shot in the head and presumed dead back in the show's first season. Cooke's surprise reappearance, confirmed at the close of the second episode of the new season, has caught many viewers off guard, though readers of Mick Herron's source novels had long anticipated the moment.
Shot and Left for Dead: How Sid Baker Survived
Sid Baker's apparent death came early in season one, first broadcast in 2022, when she was shot in the head while working a case alongside fellow agent River Cartwright, played by Jack Lowden. The moment was made all the more devastating by the palpable chemistry between the two characters. What followed, however, was not death but an induced coma, and it was later revealed that MI5 held no official record of anyone named "Sidonie Baker" ever existing.
Cooke says she filled in the blanks herself when thinking about what Sid had been through in the intervening years. "There was an intense rehabilitation process where she had to learn to talk and walk again. She made a miraculous recovery," she explained. According to Cooke, the years since have been defined by isolation and a lack of agency, with Sid kept in a kind of holding pattern under the watch of MI5 boss Diana Taverner, played by Kristin Scott Thomas.
"The years in the interim have been incredibly lonely for Sid, with a lack of autonomy as well," Cooke said. "She's been in this holding pattern with Taverner, not really knowing when she's going to be used, if she's going to be used again, or why she's being held in this certain location. Until she feels like someone is after her. And then the only person she can think of who she felt relatively safe with is River. That's why she goes hunting him down."
Cooke's Long Wait to Return to the Show
When Cooke was first cast in early 2021, she had no expectation of coming back after season one. "I was devastated because I really got invested with River and Sid, but I knew that I was always going to get shot in the head and disappear. Which is a funny thing to know," she said. After her exit, Cooke went on to achieve widespread recognition through her role in House of the Dragon, while Slow Horses continued to grow into one of the most acclaimed streaming dramas on television, accumulating 23 Emmy nominations and three wins across the past three years.
Despite her rising profile elsewhere, Cooke kept a close eye on the show and made her interest in returning known. "There were various availability checks over the years and then I was also badgering my agent because I remained such a massive fan of the show," she said. The formal invitation arrived at the end of 2024, when producers contacted her with a story breakdown for season six.
On Set: Night Shoots and a Director's Repeated Warning
Filming Cooke's return took five weeks and involved a significant number of night shoots. In the new season, Sid resurfaces just as members of the Slough House team, the collection of sidelined MI5 operatives at the centre of the series, are being hunted and killed one by one by a pair of ruthless Russian operatives played by MyAnna Buring and Kyle Soller. Sid reaches River before the Russians do, and the two go on the run together.
Cooke described the shoot as an unqualified pleasure, though director Adam Randall, the show's Emmy award-winning director, had to repeatedly pull her back into character. "Adam would have to tell me on many occasions, 'Olivia! You're being chased, stop looking like you're enjoying it!'" she recalled.
For a show that has built a reputation for putting its characters through serious physical ordeals, the return of Sid Baker marks a rare instance of Slow Horses bringing someone back rather than writing them out permanently.
