Slow Horses Reveals Olivia Cooke's Return As Sid In Season 6 Trailer

Some spies always find a way to come back... even from beyond the grave.

Apple TV has released the official trailer for Season 6 of the acclaimed spy drama "Slow Horses" (premiering Wednesday, September 16), and in it, we catch a glimpse of a familiar face: Olivia Cooke's character Sid Baker, who was supposedly killed off back in Season 1. At the end of the trailer — which you can watch above — Gary Oldman's spy chief Jackson Lamb asserts that "we've all faked our own death at one time or another," and then River is stunned to see Sid standing at the top of a staircase, where she simply says: "Hello, River."

Elsewhere in the trailer, Jackson shows up at the home of MI5 director Diana Taverner with a question: "Do you know anything about why my Slow Horses keep turning up dead?" Indeed, an alarming number of Lamb's spies are getting knocked off, and "everyone who has ever worked at Slough House is being targeted." Lamb orders his team to hide out in a safe house and stay off their phones until the danger subsides — but of course, the Slow Horses were never great at following orders.   

"Slow Horses" debuted on Apple TV in April 2022 with a six-episode freshman season, with Oscar winner Gary Oldman starring as Jackson Lamb, the cranky head of Slough House, a little-regarded unit of the U.K.'s MI5 spy agency made up of spies who failed in other units. Jack Lowden co-stars as ambitious MI5 agent River Cartwright, with Olivia Cooke as fellow Slough House agent Sid Baker. Sid was killed off in Season 1, though, when she was shot in the head during an investigation. Well, at least River was told Sid died, but he later learned Sid's records were mysteriously scrubbed, opening the door for a possible return. (Cooke went on to star as Alicent Hightower in HBO's "House of the Dragon," which premiered just a few months later in August 2022.) 

"Slow Horses" has earned strong critical acclaim since its debut, earning nine Emmy nominations for its most recent fifth season, including best drama series and acting nods for Oldman and Lowden. (Here's our ranking of all five seasons so far.) Season 6 "sees the Slow Horses on the run as Diana Taverner embroils them all in a fatally high-stakes game of retaliation and revenge," per the official synopsis.

Press PLAY at the top for a sneak peek at Season 6, and hit the comments to share your thoughts on Sid's return.