Slow Horses Season 4 Episode 4, titled 'Returns', highlighted the relationships tied to Les Arbes for River Cartwright. This was what finally gave the much-needed turn in the storyline. With this twist, it can be inferred that River's connection to Les Arbes is much closer than previously understood.
Returning from his traumatic stint in France, River found many disturbing connections between the past and the sinister operations of Les Arbes mansion. This situation would eventually redefine his relationship with his grandfather David Cartwright.
This article will explain how River is linked with the Les Arbes collective, the after-effect of Frank Harkness's plans, and how MI5 plays a role in all these events.
Frank Harkness and the London bombings on Slow Horses
In the previous Slow Horses episodes, it was revealed that Frank Harkness was behind the London bombings and tried to kill David Cartwright. However, this episode goes into his motivations and connections. Frank sits with a high-ranking member of a Royal family from the Middle East. So, he is indeed a hitman for hire.
This meeting reveals that Frank's operations are not just freelance, but are somehow roped into the international power play. Frank's failure in the Westacres bombing is multi-dimensional. He was tasked with an assassination and engineered an accident out of it.
When the supposed Robert Winters decided to detonate a car bomb, it led right back to Frank and unveiled the secrets of MI5. All this reflects the complexity of the world of espionage shown by Slow Horses, where everything is related and there are consequences, especially for agents on dangerous ground.
But, as pressure is mounting on Frank from his client to explain the failure of the operation, back goes the hero in a battle against time to take out all the remaining witnesses who could expose the links between Les Arbes and MI5.
River's findings on Slow Horses show the Les Arbes connection
The return of River Cartwright to London becomes a turning point in this Slow Horses episode, more so when he's trying to find out the truth about his grandfather's associations with Les Arbes. In investigating his grandfather's involvement, River discovers paintings that remind him of similar ones that he saw at the Les Arbes mansion.
This revelation makes him wonder if a woman connected with Les Arbes may have figured in the history of his family, specifically his ancestry. Further into the backstory, Sam Chapman recounts his experience from 30 years ago, that he had previously carried weapons and "cold bodies," which are counterfeit identities, to the Les Arbes mansion at David Cartwright's behest.
Frank Harkness, as a gang leader in the clandestine activities involving MI5, believes the past is far more bound to the present than previously thought. Then, there's the question of the mysterious woman Chapman ferries back to England after completing her secret mission. This also leaves doubts over River's paternity. The connection with Les Arbes is deeper than what coincidence would allow.
Can Cartwright and Chapman survive on Slow Horses?
With each episode, the stakes are increasingly threatening against David Cartwright and Sam Chapman. For Frank Harkness and his murderer of David, the urgency on MI5 to act is growing more critical. But, what Jackson Lamb and the Slough House people can do is to save a David with Alzheimer's, but one who may very easily get caught.
Now, it gets complicated when David, whom the treacherous Chapman and Harkness have driven blind into the old MI5 headquarters, again becomes a target. He escapes narrowly with timely intervention from Sam and Catherine Standish this time around, as is not the case for Chapman, who is brutally attacked. This shows the measures Harkness will take to clear out whoever might know the truth.
This Slow Horses episode ends with River being apprehended by Emma Flyte as revelations of his identity and connections to the Les Arbes group unfold.
The fact that River evaded the agents from MI5 suggests that however desperate he was for answers, he remains a fugitive in the very world he was trying to know.
Fans of the Slow Horses series can watch Season 4 through Apple TV+ with only two episodes left this season.