Season 4 of the Apple TV+ spy thriller Slow Horses has kicked off with two intense episodes. The plot centers around Jackson Lamb (played by Gary Oldman) and his team at Slough House as they tackle a new danger in London.
The storyline comes from Mick Herron’s fourth novel, Spook Street, which focuses on MI5’s response to the terrorist bombing at Westacres in downtown London.
But this season adds a second plot. It focuses on River Cartwright (played by Jack Lowden) and his grandfather, David Cartwright (played by Jonathan Pryce). Both characters are in serious trouble after shocking developments in Episode 2. The series also introduces Frank Harkness (played by Hugo Weaving), a new villain.
How the Cartwrights Landed in Danger
In the first two episodes, David mistakenly shoots someone in his home. At first, he thinks the person is River, but later it’s revealed to be an assassin named Robert Winters. David is experiencing dementia-like episodes and can’t clearly explain why he shot the man.
River helps cover up the murder and then travels to France to investigate Winters’ past. Catherine Standish (Saskia Reeves) provides a safe house for David, but he keeps talking in circles when Jackson Lamb asks him about River’s whereabouts. Jackson believes that David might be pretending to be confused.
Meanwhile, River arrives in Lavande, a quiet town in France. He finds Winters’ house and searches through his belongings. However, he is caught by Frank Harkness.
Harkness is connected to the Westacres bombing and wants to keep River from linking him to Winters. Just as it seems Harkness might kill River, a mysterious Frenchman shows up and drives Harkness away with a shotgun.
After escaping from the burning house, River thanks the man but is knocked unconscious by the butt of his gun. The man then drives them both away. The episode ends on this cliffhanger, raising several questions.
Who is helping River and David Cartwright if it’s not MI5 or Slough House? The Frenchman was seen tracking River earlier, but who is he working with?
What’s Frank Harkness Hiding?
Hugo Weaving joins Slow Horses in Episode 2 as Frank Harkness. So far, Harkness’ role in the story remains a mystery, but it’s clear that he’s connected to the Westacres bombing. He appears to be an American, and he’s controlling the events surrounding the bombing.
His attempt to stop River in Lavande shows he is now directly involved in the Cartwrights’ storyline. More will likely be revealed about Harkness and his motives in Episode 3.
Although Diana Taverner (Kristin Scott Thomas), the deputy head of MI5, hasn’t been directly involved with the Cartwrights yet, she knows about Robert Winters’ fake identity, which MI5 created 28 years ago.
Taverner’s story will likely intersect with the Cartwrights and Jackson Lamb as the season progresses. The Westacres bombing will tie all their fates together.
Is David Cartwright Faking Dementia?
Catherine Standish has offered David Cartwright a safe place to stay after the shooting. While David appears to be confused and in shock, he also has moments of clarity. Based on Jackson Lamb’s strong instincts, it seems likely that David is pretending to be more confused than he is. The bigger question is why David would fake his condition.
Jonathan Pryce plays David convincingly as a scared, frail old man. However, David is also a former MI5 agent, which means he may be deceiving everyone for a reason. As the story unfolds, we will learn more about why he’s acting this way.
Slow Horses Season 4 is available on Apple TV+ in the U.S., with new episodes released every Wednesday.
