Slow Horses Season 6 Episode 2, “Daddy Issues,” turns the threat circling Slough House into something much more immediate. Gary Oldman’s Jackson Lamb realizes the old team has been exposed, Jack Lowden’s River Cartwright gets pulled deeper into the orbit of his father Frank Harkness, and the episode ends with the return fans have been waiting years to see: Olivia Cooke’s Sidonie “Sid” Baker is alive.
It is a propulsive follow-up to “Circle of Life,” moving between a deceptively tidy murder investigation, a badly compromised MI5 archive and River’s increasingly personal pursuit of Hugo Weaving’s Harkness. The title promises paternal damage; the episode delivers it, while making clear that the danger to Slough House is not merely a family matter.
This recap discusses all major plot developments and the ending of Slow Horses Season 6 Episode 2, “Daddy Issues.”
Kay White’s Death Is Not an Accident
The episode’s first important correction is a grim one. Kay White’s apparent death is not an accident, and Shirley Dander and J.K. Coe are quick to see the pattern: somebody is deliberately working through people with ties to the old Slough House roster. That turns the Season 6 premiere’s unease into a proper operational emergency. The killers, the polished and unnervingly calm Jim and Jane, have a list and the confidence of people who expect no resistance.
Their next target is Moira Tregorian. Posing as workers responding to a gas leak, they gain access to her house, flood it with gas and kill her. It is a quietly horrible sequence precisely because it is so routine. No rooftop chase or elaborate trap is necessary; a former intelligence officer can be erased in the kind of domestic accident that barely causes a ripple. The message is unmistakable: these killers know the system, know the people in it and can get to the old Slow Horses wherever they live.
Frank Harkness Is Connected to the Stolen Files
Meanwhile, River cannot let Frank’s appearance at David Cartwright’s funeral go unanswered. He asks Roddy Ho to track his father’s rental car, and the trail brings River and Lamb to the home of Andrew Nesmith, a former Dog. Nesmith is dead by the time they arrive, in a scene arranged to read as suicide. Lamb and River do not buy it.
The wider scheme starts to take shape. Nesmith had accessed Molly Doran’s archive and stolen a sensitive MI5 file containing the records of Slough House agents. The theft was tied to Damien Cantor, a wealthy media operator with a political connection to Peter Judd, and Frank is part of the chain that gets the work done. When Nesmith became a liability and started applying pressure to the people who hired him, he was removed.
River spots a CCTV camera near Nesmith’s home, and the footage reveals a child at the crime scene — one more unsettling detail in a season already shadowed by Frank’s history of turning children into tools. The clue does not answer every question, but it gives River a reason to keep following his father even as Lamb is trying to protect the living members of the team.
Slough House Has Been Wiped Off the Board
Lamb’s conversation with Molly supplies the episode’s most alarming piece of operational information. The stolen file is not simply a useful roster; Slough House’s physical records have been erased from the Park’s systems. That is how the assassins can identify and isolate their targets while official MI5 channels appear blind to the problem. The team has not merely been watched. It has been deliberately made harder to find and defend.
For Lamb, that means the usual Slough House improvisation is no longer enough. He orders his people to meet at Blake’s Grave, turn off their phones and go dark. It is a smart escalation because it shifts the season’s central question. The Slow Horses are not chasing a mystery from the safety of their decrepit office now; they are the quarry, and any routine contact can be used to locate them.
River Finds Sid Baker
River, of course, is only half able to follow Lamb’s instructions. His questions about Frank and the evidence left behind pull him back to David’s house, where “Daddy Issues” ends on its biggest revelation: Sid Baker is there, very much alive.
Sid was presumed dead after being shot in the head during the first season, then quietly erased from the board by MI5. Her return is not treated as a victory lap or an easy explanation. River gets the shock before he gets the answers, which is exactly right. Sid’s survival raises immediate questions about who protected her, why she was kept from the people at Slough House and how her apparent connection to Russian business fits the danger now moving around London.
Final Verdict
“Daddy Issues” does the valuable second-episode work of converting a strong premiere into a season engine. The murders are uglier and closer, Frank’s connection to the data breach makes the conspiracy feel personal without shrinking it to River’s trauma, and Sid’s return gives the ending genuine charge. Some of the wider Cantor-Judd machinery is still being positioned, but the episode knows exactly when to stop explaining and let the dread do the work.
The Old Horses Are in the Crosshairs
A sharply escalating second chapter turns the file breach into a survival problem and ends with one of the series’ most welcome returns.
River reaching David’s house and finding an impossible figure from Slough House history waiting there.
Gary Oldman, who makes Lamb’s order to disappear feel both brutally practical and oddly protective.
The murderous threat gets concrete, River’s family story gains purpose and Sid’s reveal arrives at exactly the right moment.
The larger Cantor-Judd plot is still more setup than payoff, though that gives the season room to build.
Ending Explained: Why Is Sid Back?
Sid’s return confirms what the series has carefully left ambiguous since Season 1: she survived the shooting that removed her from Slough House. “Daddy Issues” does not yet give River — or viewers — the complete account of how that happened, why MI5 let everyone believe she was dead or what she has been doing in the years since. It does establish that her absence was not a loose end. It is part of the same hidden world now closing in on Lamb’s team.
The ending also lands because River has just lost David, the grandfather who raised him, while Frank has reappeared as the biological father he cannot trust. Sid was once one of River’s earliest partners at Slough House. Seeing her alive does not solve his family crisis, but it restores a piece of the professional family River thought was gone forever — and immediately makes that reunion dangerous.
Slow Horses Season 6 Episode 2 FAQ
Who killed Moira Tregorian?
Jim and Jane kill Moira after posing as workers investigating a gas leak at her home. Her death confirms that former Slough House personnel are being systematically targeted.
What did Andrew Nesmith steal?
Nesmith stole a sensitive MI5 file containing records connected to Slough House agents. The breach gives the people hunting the team the information they need to locate former and current members.
Is Sid Baker really alive?
Yes. The final scene reveals Sid alive at David Cartwright’s house, though the episode deliberately withholds the fuller explanation for her disappearance and survival.
Is Frank Harkness behind the murders?
The episode links Frank to the stolen-file operation and makes him central to the danger around Slough House. It does not fully close the case on who is directing every murder or why the team was selected.
Where to Watch Slow Horses
Slow Horses Season 6 Episode 2, “Daddy Issues,” is streaming now on Apple TV. New episodes arrive weekly on Wednesdays; Season 6 Episode 3 premieres Wednesday, September 30. Seasons 1–5 are also available to stream on Apple TV.
Catch up with our Season 6 premiere recap and ending explained, revisit the “Daddy Issues” photos, and follow Seat42F’s complete Slow Horses coverage for news, photos, promos, recaps and reviews.
Thomas Miller is the founder and Editor-in-Chief of Seat42F, covering television, movies and streaming entertainment. He launched Seat42F in 2007 and has spent nearly two decades covering the entertainment industry.
