The sixth season of Apple TV+’s acclaimed spy drama Slow Horses introduces a pivotal new character, Reese Nesmith, played by 17-year-old BAFTA winner Lenny Rush. Following the season premiere on September 16, 2026, Rush’s portrayal of a young witness caught in a web of MI5 intrigue has become a central focus of the new episodes.
In the series, Reese Nesmith is the son of former MI5 agent Andy Nesmith. His introduction in the second episode, titled “Daddy Issues,” sets the stakes for the season as Reese becomes a witness to his father’s murder. This development forces the rejects of Slough House to navigate a dangerous landscape while protecting a child who holds the key to a larger conspiracy.
Adapting the Books: From Adult to Child
Season 6 represents a significant shift in how the series handles Mick Herron’s source material. This season adapts two novels simultaneously: Joe Country and Slough House. To streamline these narratives, showrunner Gaby Chiappe—who took over the role from Will Smith for this season—implemented a major change to the character of Reese Nesmith.
In Herron’s novels, Reese Nesmith III is an adult gay American dwarf. The television adaptation reimagines the character as a British teenager, a choice that alters the emotional tenor of the storyline. By making Reese a child witness rather than an adult operative, the show emphasizes the vulnerability of those caught in the crossfire of the intelligence services’ “dirty games.”
Who is Lenny Rush?
Lenny Rush’s casting in Slow Horses Season 6 follows a period of rapid professional growth for the young actor. Born in March 2009, Rush first gained widespread recognition and a BAFTA for his performance in the comedy series Am I Being Unreasonable?
His involvement in the Apple TV+ series is not his only high-profile project. Rush has also been cast as the house-elf Dobby in the second season of HBO’s upcoming Harry Potter television reboot. His role as Reese Nesmith showcases a dramatic range compared to his earlier work, anchoring the emotional stakes of the Slough House team’s latest mission.
The current season of Slow Horses is scheduled to run weekly on Apple TV+, with the narrative expected to conclude its arc by late October 2026.
