A Ghost From the Past Returns in New ‘Slow Horses’ Season 6 Trailer

Gary Oldman ’s irascible spy boss Jackson Lamb is trying to get to the bottom of who’s killing off his Slough House agents in Apple TV ’s new trailer for season six of Slow Horses — even if he thinks they’re all worthless.

Along with the trailer release, the streamer has announced the return of Olivia Cooke ( House of the Dragon , Ready Player One ) as Sid Baker, an agent who was believed to have died back in season one.

Slow Horses season six premieres Wednesday, Sept. 16, with one episode dropping each week through Oct. 21. The trailer (which you can watch below) starts with Oldman comically antagonizing his boss, MI5 First Desk Diana Taverner (Kristin Scott Thomas), before asking her if she knows why current and former members of his Slough House division keep showing up dead. Related Stories TV 'Ted Lasso' Season 4 Sets Premiere Day Viewing Record for Apple TV TV What Showrunner Will Smith's Exit Means for 'Slow Horses' Season 6

The team then starts to investigate, piecing together that they’re being targeted. “It’s a bloodbath,” Lamb says.

Everyone who’s connected to Slough House is rounded up at a safe house and told to go off the grid, including Louisa (Rosalind Eleazar), who previously announced her intention to quit after she went on a mental health break in season five.

“Stay dark, no phones.” Lamb admonishes them, but the order is seemingly ignored by several characters, including tech expert Roddy (Christopher Cho), who subsequently answers his phone.