The fifth season of Apple TV+’s hit spy thriller Slow Horses concluded with an explosive finale titled “Scars,” leaving a trail of resolved crises, shocking personal revelations, and a transformed power structure at MI5. The Slough House team once again cleaned up a mess that the main agency couldn’t handle, preventing a devastating terrorist attack while uncovering deeper conspiracies. The episode, which premiered on October 29, 2025, delivered on both action and character depth, culminating in a major promotion and a haunting glimpse into Jackson Lamb’s past.
The Final Attack at Abbotsfield
The season finale picked up with MI5’s systems still frozen by a virus planted by Tara, a member of the Libyan group carrying out a “destabilization strategy” against the UK. With an hour-long countdown on their screens, MI5 received a call from Tara, who was holding the Libyan ambassador at gunpoint. She laid out her demands: $100 million and safe passage out of the country. If her demands were not met, she promised an attack on a place of worship in London on a Sunday morning.
While MI5 leadership scrambled, Jackson Lamb deduced the likely target. He told his team that only one place would occur to a “complete and utter psychopath,” and J.K. Coe immediately understood. The target was the multi-faith center at Abbotsfield, the site of a previous massacre, where Mayor Zafar Jaffrey was commemorating the lives lost. River Cartwright, Shirley Dander, and Coe raced to the scene to evacuate the crowd.
Despite Mayor Jaffrey’s initial disbelief and a frustrating call from First Desk Claude Whelan insisting the threat was over, the Slough House agents proved to be correct. Two attackers, Farouk and Kamal, arrived and opened fire. In a tense standoff, Shirley Dander shot and killed Kamal after Coe handed her his weapon. When Farouk took Jaffrey hostage, the agents’ bickering distracted him long enough for Coe to sneak up and stab Farouk with a small knife, neutralizing the threat.
A Sting in the Tail and a Personal Target
With the shooters dead and Tara in custody, it seemed the crisis was over. However, a conversation with his grandfather, the legendary MI5 agent David Cartwright, sparked a realization in River. His grandfather mentioned an old, unwritten rule of destabilization: a “sting in the tail,” or a final attack when the enemy thinks the danger has passed. River remembered that the original photo of the terrorist team showed four men, not three.
Lamb connected this to Tara’s earlier efforts to access Whelan’s personnel file. Realizing that Whelan himself was the final target, River raced to find the First Desk, who was jogging alone in a park. He arrived just in time to save Whelan from Sami, the fourth terrorist, whose family was killed in Libya after Whelan, as a government forecaster, had advised the UK to withdraw from the conflict.
Jackson Lamb’s Blackmail and a New First Desk
After River saved his life, Claude Whelan planned to make Slough House the scapegoat for the entire security failure. He went to Lamb’s office to shut down the unit for good. However, Lamb had a final card to play. He revealed a recording of Whelan attempting to blackmail another official, Dennis Gimball, hours before Gimball was killed.
Confronted with this damning evidence, a defeated Whelan was forced to agree to Lamb’s demands: resign as First Desk, leave Slough House alone, and reinstate both Molly Doran and Roddy Ho. This orchestrated resignation finally allowed Diana Taverner to achieve her long-standing ambition and become the new First Desk of MI5. In a final phone call with Lamb, she confirmed that she would not be taking River Cartwright back to the Park, ensuring he would remain at Slough House.
The Haunting Truth Behind Lamb’s Scars
The finale’s title, “Scars,” paid off in a deeply personal reveal for Jackson Lamb. Earlier in the season, Lamb had told a dark story about a young spy in Berlin who was captured and tortured by the Stasi. The spy was forced to watch as the woman he loved, who was pregnant with his child, was brutally tortured and killed because his captors believed he had a name they wanted. Lamb claimed the story was made up.
The final scene of the season showed Lamb in his office, taping up an old sock. As he propped his bare foot on the desk, the camera revealed the bottom was brutally burned, scarred, and scaled. This visual confirmation suggests that the horrific story Lamb told was, in fact, a story from his own past, revealing the deep trauma that shaped the cynical and abrasive man he is today. Gary Oldman revealed that this pivotal reveal was suggested by his wife, who felt the audience, not another character, should be the one to see Lamb’s scars.
River Cartwright’s Stalled Ambition
The finale also left River Cartwright at a personal crossroads. After saving Whelan, he was certain he had earned his ticket back to MI5 headquarters, known as “the Park.” He confidently told Lamb, “I shouldn’t be in Slough House, because I’m really good and you know that.” He even left a voicemail for former colleague Louisa Guy, telling her he was leaving.
However, Lamb’s deal with Whelan and Taverner ensured that River would stay at Slough House. While Lamb would never admit it, his actions suggest a mix of motives: a desire to keep his “punching bag” and a belief that River still has more to learn outside the corrupting rules of the Park. As a result, River enters the next season knowing he is capable but stuck in a place he feels he has outgrown.
How the Plot Unraveled
The web of the season’s conspiracy became fully clear in the finale. The group of Libyan extremists, including Tara, sought revenge on the UK for its historical exploitation of their country. They hired former Home Secretary Peter Judd to help them blackmail the government, setting up an offshore Cayman Islands trust called Albion Holdings for the ransom money. Judd was the director of this trust.
When Judd failed to deliver, the group took matters into their own hands, carrying out the series of attacks. Tara’s role was to infiltrate and compromise MI5 by dating Roddy Ho, which gave her the access needed to plant the system-shutting virus. While Tara was willing to take the money and flee, the other members, particularly Farouk, were more committed to the cause and intent on carrying out the final act of carnage regardless of the payment.
Also Read: Slow Horses Season 6: Is There a Release Date? Here’s What We Know
