Slow Horses continues to deliver some of the sharpest writing and most compelling character work on television in its sixth season, and Lost And Found continues the show’s expertise at sustained tension blended with it trademarked dark humour and ability to shock. This episode tightens the screws on every major player while advancing the season’s two conspiracies with efficiency and style. From the neon glow of a suburban bowling alley to the cold calculations of high level intelligence offices, the episode builds an atmosphere of mounting dread that gets its hooks into you.
The episode picks up directly from the previous cliffhanger with River Cartwright, Sid Baker, and J.K. Coe on the run and in desperate need of a way to contact Diana Taverner. Their search leads them to a Nova Bowl bowling alley where the mundane obstacles of everyday life collide hilariously and then horrifically with a high stakes game of cat and mouse. The extended scene involving the stubborn cashier Phil, who refuses to allow access to the payphone because he is closing up, is all too real and provides one of the season’s purest comic highlights. River’s awkward attempts at persuasion, including an ill advised cash offer that is immediately called out as a bribe, showcase Jack Lowden’s impeccable timing and the easy chemistry between him and Olivia Cooke’s Sid. The colourful neon lights, arcade sounds, and the unexpected needle drop of A ha’s “Take On Me” create a vivid, almost nostalgic atmosphere that takes you back to the West versus East spy stories of the ’70s and ’80s.
Once again escaping by the skin of thier teeth, the heroes end up hiding out in a motorway service station. While River and Sid bicker and scheme, Coe occupies himself with a racing simulator in the arcade. His sharp instincts kick in when he spots the Russian wet team of Jim and Jane. The decision to follow Jim into the men’s room sets up one of the most memorable confrontations in the series. What begins as a strangely civil exchange between two professionals who recognise something of themselves in each other quickly turns deadly. Coe correctly identifies Jim’s Russian military background, specifically GRU, and even offers the pointed observation that the hit squad may be working from the wrong list. The knife fight that follows is largely kept off screen, yet the aftermath is devastating. River arrives too late to intervene and discovers Coe’s lifeless body. Tom Brooke has brought a quiet unnerving intensity and dry wit to Coe across previous seasons, and his sudden exit carries genuine weight. The moment underscores the show’s ongoing willingness to raise the personal cost for its characters without hesitation.
Outside in the carpark, the situation deteriorates further. Sid’s determination to reach Diana despite River’s vocal objections proves catastrophic. Jane seizes the opportunity while River is distracted, and Sid is taken. River is left stranded without backup, vehicle, phone, or weapon, watching Coe’s car speed away with Sid inside. The scene is executed with taut precision, and the sense of helplessness is palpable. Sid’s trust in the First Desk has always been complicated, and the episode makes clear that this particular leap of faith was a profound miscalculation.
Meanwhile, at the Park, Diana Taverner finds her position under increasing strain. Oliver Nash confronts her with uncomfortable questions about the Kazan incident, previously framed as a robbery gone wrong. The victim was a GRU agent connected to a Novichok plot on British soil, and the retaliation appears to have been an unauthorised operation that Diana must now account for. A call from Vassily Rasnakov, Russia’s equivalent of First Desk, ups the stakes dramatically. Vassily is furious about the hit on Russian soil and demands the agent responsible. Travel documents issued in the name of Sidonie Baker make Sid the convenient scapegoat. Diana’s decision to agree in principle to hand Sid over in exchange for an end to the targeting of other agents on the list doesn’t brake from what you would expect from the character: cold, strategic, and ultimately self preserving. Kristin Scott Thomas conveys the internal calculation with both the institutional logic and the personal betrayal involved.
The episode doesn’t lose sight of Jackson Lamb, who is continuing his own investigation into Frank Harkness. Using Reece as leverage, Lamb engineers a meeting that eventually leads to a Shake Shack confrontation and further surveillance. The trail ultimately connects Frank to media mogul Damien Cantor. Lamb’s methods remain as unorthodox and foul mouthed as ever, yet Gary Oldman’s performance continues to reveal new layers of cunning beneath the layers of cynicism and bodily neglect. The involvement of Emma Flyte, former Head of the Dogs, adds another reluctant alliance and more institutional friction. Lamb’s ability to extract cooperation from people who would rather have nothing to do with him remains one of the series’ great pleasures.
The episode balances its multiple threads with a high level of skill. The personal stakes for River and Sid are immediate, while the larger geopolitical and bureaucratic machinations involving Diana, Vassily, Cantor, and Frank provide the necessary sense of scale. River’s protectiveness and growing frustration with Sid’s choices, Sid’s residual belief that the system can still be navigated, and Coe’s fatal professionalism all ring true.
The revelation that the Russians are operating from a flawed understanding of who carried out the Kazan operation deepens the sense that multiple agendas are colliding. Cantor’s continued manoeuvring, the question of who Frank’ is ultimately working, and Diana’s willingness to betray an agent, create dangers from all sides. At the same time, the personal losses accumulate. Coe’s death is not merely a plot device but a reminder that the characters the you has grown attached to over multiple seasons are vulnerable. Sid’s capture raises the immediate question of how River will respond and whether Diana’s bargain will hold or fracture under further pressure.
The performances across the board are once again outstanding. Lowden and Cooke share a charged rapport that mixes residual affection, professional friction, and mutual distrust. Brooke makes Coe’s final scenes count. Scott Thomas continues to refine Diana into a fascinatingly amoral figure. Oldman needs only a few well chosen lines and a withering look to dominate every scene he occupies. Kyle Soller and MyAnna Buring playing Jim and Jane, maintain the necessary menace and cold professionalism that the Horses are missing without tipping into caricatures of Russian agents.
The show balances the humour and horror in the situation, having them coexist without cancelling each other out. The absurdity of arguing with a cashier about a payphone while professional killers close in feels entirely consistent with the world series has built. The moral compromises of the intelligence services are presented without preaching. Characters make choices according to their own warped senses of loyalty and survival, and the consequences follow with unforgiving logic.
When the episode ends with Sid in the hands of the assassins and River isolated, you need to know what happens next. The various strands of the conspiracy have been drawn tighter. Personal costs have been paid. Trust has been further eroded. Lost And Found demonstrates once again why Slow Horses remains essential viewing. Its tightly constructed, emotionally resonant, and consistently engrossing from its deceptively light opening moments through to its bleak cliffhanger.
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Where to watch Slow Horses – Season 6, Episode 4: Lost And Found: