Apple TV has released the first trailer for the sixth season of its spy thriller Slow Horses, confirming the return of Olivia Cooke as Sidonie Baker and Rosalind Eleazar as Louisa Guy.
Cooke's character, Sid, had a memorable but brief role in the show's first season in April 2022. Her departure was described as dramatic, and her story arc remained unresolved, leading to consistent speculation and fan demand for her return. The series, based on Mick Herron's Slough House novels, has now caught up to the point where Sid's reappearance was possible within the source material's narrative.
The trailer also features Gary Oldman as the gruff Jackson Lamb, who manages the MI6 agents relegated to Slough House, and Kristin Scott Thomas as Diana Taverner, the head of MI6. The upcoming season appears to place the Slough House agents in danger, with Kyle Soller portraying one of the antagonists. Lamb is depicted attempting to protect the current staff and former agents from harm.
Rosalind Eleazar's character, Louisa Guy, is also back, despite having stated her intention to leave espionage at the beginning of Season 5. Additionally, the trailer hints at further conflict between River Cartwright, played by Jack Lowden, and his father, Frank Harkness, portrayed by Hugo Weaving.
Slow Horses has maintained a consistent release schedule, with new seasons premiering annually since its debut, with the exception of Season 2 which followed Season 1 in less than a year. Season 6 is set to adapt two books from Mick Herron's series, Joe Country and Slough House, deviating from the usual one-book-per-season format. A seventh season has already been confirmed.
The first episode of Slow Horses Season 6 is scheduled to premiere on September 16 on Apple TV, with new episodes released weekly.