After Gary Oldman, Olivia Cooke was arguably Slow Horses‘ biggest star when it premiered in 2022. Before joining the spy series, she had starred in Bates Motel, Me and Earl and the Dying Girl, Thoroughbreds​​​​​, and more. In addition to being a talented and reputable actress, her character was among the biggest points of intrigue established in the show’s opening episode.

All of this made it all the more unexpected when Cooke’s Sid Baker was shot in the head in the show’s second-ever episode and hasn’t been seen since. That is, until her equally surprising return at the end of Slow Horses season 6, episode 2, “Daddy Issues.”

Moments before her perceived death in Slow Horses season 1, Sid, who was uncharacteristically competent for a spy relegated to Slough House, admitted to River that she had been planted there by First Desk Diana Taverner to spy on River. Before he could ever find out why, Sid became a casualty in a mission gone wrong.

For all intents and purposes, Slow Horses forgot about her for years after that. Sid was presumed dead, and everyone from River to Jackson Lamb seemed either satisfied with this explanation or too distracted to look into it further.

Now that she’s returned, though, both her disappearance and her presence in the first place seem highly suspect. Cooke’s return to Slow Horses is an exciting development for the show, especially as the nature of her return creates even more questions than it answers, as it defies this season’s premise, one that was already engineered to see the return of many forgotten Horses.

Sid Baker’s Return Suggests Frank Harkness Has Been Around From The Start

“Daddy Issues” saw River impatiently waiting for Roddy to trace the location of several mysterious calls he’d received, as he assumed his murderous father, Frank Harkness, was the caller. When Roddy finally pinned the calls down to the home of River’s own late grandfather, River promptly kicked Roddy out of the car and went there alone to confront Harkness. Instead, River came face to face with Sid Baker.

Since her presence is all that “Daddy Issues” confirmed about Sid, it’s possible that her reappearance has nothing to do with Harkness, but this seems unlikely. Harkness seems to have a connection to and fixation with Slough House and its agents that dates back even farther than the character’s introduction in the series.

It would be very odd for Sid’s return, after all these years, to coincide with Harkness’ hunting of Slough House agents as a mere coincidence, especially considering the unnatural and highly suspicious way she went about contacting River.

Separately, “Daddy Issues” also demonstrated that Taverner, who originally gave the orders for Sid to spy on River, can be manipulated financially. Furthermore, she doesn’t even always know where that money is coming from. Slow Horses season 1 never revealed why Taverner instructed Sid to tail River, but “Daddy Issues” created the possibility that it could have been at the financial behest of Harkness.

Even if it wasn’t, it’s just as, if not more, likely that Harkness intercepted Sid after her shooting and hospitalization. He clearly has an interest in River, as well as other mysterious and seemingly nefarious objectives involving the Slow Horses, and Sid, a capable and presumed-dead Slough House double agent, would likely be a great tool for him.

Sid may have been beholden to Harkness all this time following her season 1 disappearance.

River Lost Interest In Sid Too Quickly In Slow Horses’ Early Seasons

River was shocked in the immediate aftermath of Sid’s revelation and subsequent shooting, and understandably had some questions. However, within a few episodes, River’s mind seemed to have moved away from Sid and onto other, more immediate problems.

River’s characteristic impulsivity and lack of forethought make his ability to move on from this bizarre situation believable. However, his intuition, resourcefulness, and persistence would likely have yielded some results if he had stayed focused on learning everything he could about Sid, and this could have better prepared him for her return, which took him completely by surprise.

Somewhat less believable is the fact that even Lamb seemed to accept Sid’s illogical presence in Slough House and subsequent vanishing. Lamb, even more intuitive, resourceful, and persistent than River, should have immediately questioned the highly competent Sid’s presence in Slough House, as well as her complete disappearance after being shot.

Yet the character hasn’t been mentioned by anyone for years. The complete lack of information and even thought given to Sid makes her character Slow Horses‘ oldest mystery, though one the show is primed to finally solve in season 6.

Release Date

April 1, 2022

Network

Apple TV+

Showrunner

Douglas Urbanski

Directors

Adam Randall, James Hawes, Jeremy Lovering, Saul Metzstein

Writers

Mark Denton, Jonny Stockwood