River Cartwright Survives Poisoning in Slow Horses Season Six

River Cartwright survives a poisoning attack at the end of Slow Horses season six, although the incident leaves him with lingering health problems that could limit his appearance in the next season. The finale places the MI5 agent at his grandfather's old house, where he encounters a poisoned metal handle while searching for Sidonie, his fellow spy and love interest. The substance causes River to struggle for breath and collapse on the floor while Sid remains unaware of the danger upstairs.

According to the novels by Mick Herron, Russian assassins use a nerve agent against River, but he survives after Sid discovers him and secures help. The attack has consequences beyond the immediate emergency. River experiences vision problems, fatigue, and dizziness during his recovery, leaving him unable to return to active duty straight away.

In Bad Actors, the eighth novel in Herron's series, River remains on medical leave while recovering from the poisoning. The storyline provides a basis for a reduced role for the character in the television adaptation's seventh season.

Season seven is expected to adapt Bad Actors after season six combined material from two novels. The extent of River's involvement in the upcoming season has not been confirmed in the source report. The character's absence from active duty could also affect the screen time of Jack Lowden, who plays River. Lowden has been widely rumored to be a contender for the role of James Bond, raising questions about how he could balance a potential film commitment with his work on Slow Horses.

Slow Horses has also been renewed for an eighth season, according to the source report. River's recovery storyline could provide flexibility for the production if Lowden takes on other projects, although no confirmed casting announcement for Bond is cited. River eventually returns to active duty in Clown Town, the ninth novel in Herron's series. The book follows him as he waits for medical clearance and investigates secrets connected to his late grandfather, a legendary former spy, including a mysteriously missing book from the old man's library.