Episode 1 of *Slow Horses* Season 5 opens with a man exiting his apartment and taking a seat directly across from a political campaigner in a bustling town square. The campaigner is fervently advocating for Mayor Jaffrey's ascension, but the man across from him is unimpressed. In a shocking twist, he snatches up a machine gun and unleashes a hail of bullets across the square, mowing down everyone in his path.
From a vantage point afar, a sniper expertly takes him out with a precise headshot and nonchalantly walks away, disappearing into the same white van we glimpsed earlier. As the van speeds off down the road, it nearly collides with Roddy, who is prancing about the street in a comical imitation of Star Lord. Shirley, with lightning reflexes, shoves him out of harm's way, but Roddy's primary concern is his headphones, which have been shattered to pieces by the oncoming traffic.
Determined to unravel the mystery of the white van's owner, Shirley approaches Jackson as he's enjoying his breakfast. He responds with a barrage of curses, ordering her to leave. However, after the traumatic events of last season, including Marcus's death, Shirley is on high alert, viewing every potential assassin as a looming threat to the team. Among her colleagues, only Catherine seems to grasp the gravity of her fears.
Emma Flyte arrives at the crime scene and, after delivering a stern rebuke to one of the officers, is shown the victim's body, the surrounding area, and the gunman's apartment. She surmises that the killing might be politically motivated, noting the presence of books about Mayor Gimball in the gunman's residence.
Flyte quickly realizes that there are no eyewitnesses who saw the gunman take his own life, effectively shattering that alibi. The case is far from closed. Realizing they're dealing with a sniper, Emma meticulously scours the area and stumbles upon the sniper's nest. Conveniently, she also uncovers the bullet casing at the scene.
With eleven lives lost and tensions running sky-high, Diana finds herself navigating a perilous political labyrinth while simultaneously juggling the intricate logistics of the ongoing investigation. Claude, ever the determined sleuth, arrives at the venue set to host the impending Mayoral Debate between Gimball and Jaffrey. Both politicians are present, their mutual disdain palpable in the charged atmosphere.
Gimball appears dismissive, treating the situation with a casual air, but Claude is in no mood for games. He points out that the gunman had a photograph of Gimball and the politician prominently displayed on his refrigerator, and that his string of targeted assassinations included a campaigner from a previous incident.
Back at MI5, it's revealed that the gunman is none other than Rob Trew. On the surface, he seems like an average Joe, but his online footprint tells a different story. He was active on a website called The Unseen, a digital haven for disaffected men to voice their grievances and discuss their fears. The officers speculate that he may have felt scorned by women and overlooked by society, convinced that his British identity was under threat. His final message hints at being handed a weapon and given free rein, only to be executed by a sniper moments later.
Meanwhile, at Slough House, River updates Louisa on the dire state of his family affairs. David's condition has taken a turn for the worse since last season, and River confides his worries to Louisa. The conversation casts a somber shadow over what was meant to be Louisa's last night. Indeed, the entire evening is tinged with melancholy, with Shirley bursting in with footage of the van driver's boots, which seem to suggest a military connection. She clashes with River over the significance of the evidence, and he responds with a cutting remark about Marcus, forcing her out the door.
Outside, River attempts to broach the subject of Louisa's impending absence with her. She's about to embark on a six-month hiatus, but the possibility of not returning looms large in her mind. She knows River is struggling with his father's deteriorating health, and as he leans in for a kiss, it only serves to deepen the sense of despair. Louisa yearns for space and, more importantly, a semblance of normalcy away from the chaos. Their parting is bittersweet, leaving their future together uncertain.
Among all this, Catherine stands out as the only one taking the white van situation seriously. She believes Shirley is onto something and decides to provide her with backup that night as she follows an unsuspecting Roddy. They make their way to a nightclub, and Shirley trails behind, but Catherine, wary of the alcohol-fueled environment, opts to stay outside and calls River for assistance.
Unfortunately, Shirley's night takes a turn for the worse inside the club. She leaps onto a guy on the dancefloor in a fit of rage before dashing off to the toilets to indulge in some drugs. River gives chase, but Shirley is a wreck, in no mood to heed River's self-righteous advice.
As Roddy makes his exit from the club, arm linked with this mysterious woman, Shirley isn't far behind. In a burst of unexpected rebellion, she delivers a sharp smack to a bouncer's head and swipes a bicycle in a daring getaway. Yet, amidst this chaos, it becomes glaringly obvious that Roddy's companion holds no romantic interest in him. She skillfully evades his attempted kiss, and once she deposits him alone at his apartment doorstep, she swiftly pulls out her phone to send a message, informing someone of Roddy's whereabouts.
