THE NINTH BOOK IN THE SERIES BEHIND SLOW HORSES, AN APPLE ORIGINAL SERIES NOW STREAMING ON APPLE TV+
The bad spies of MI5's Slough House are caught in a deadly battle between MI5's secret past and its murky future in this gripping, hilarious, and heartbreaking new thriller by Mick Herron, “the le Carré of the future” (BBC).
“Old spies grow ridiculous, River. Old spies aren’t much better than clowns.” Or so David Cartwright, the late retired head of MI5, used to tell his grandson. He forgot to add that old spies can be dangerous, too, especially if they’ve fallen on hard times—as River Cartwright is about to learn the hard way.
David Cartwright, long buried, has left his library to the Spooks’ College in Oxford, and now it turns out that one of the books has gone missing. Or perhaps it never existed . . . Now River, once a “slow horse” of Slough House, MI5’s outpost for demoted and disgraced spies, has some time to kill while waiting medical clearance to return to work, and investigating the secrets of his grandfather’s library seems a harmless activity. But nothing involving the slow horses ever stays harmless for long.
Over at the Park, MI5 First Desk Diana Taverner is in a pickle. An operation carried out during the height of the Troubles laid bare the ugly side of state security, and those involved are threatening to expose details. But every threat hides an opportunity, and Taverner has come up with a scheme in which the would-be blackmailer is a solution to a much newer problem. All she needs is the right dupe to get caught holding the bag.
Jackson Lamb, the enigmatic and odiferous head of Slough House, does not want any of his joes involved. When Taverner starts plotting mischief people get hurt, and Lamb has no plans to send in the clowns. On the other hand, if the clowns ignore his instructions, any harm that befalls them is hardly his fault.
But they’re his clowns. And if they don’t all come home, there’ll be a reckoning.
The series
In a genre often defined by flawless operatives and polished espionage, Slough House takes a delightfully different path. These are not the spies entrusted with the nation's greatest secrets. They are the castoffs, the mistakes, the agents who failed once and were quietly pushed into a forgotten corner of British intelligence. Yet from that unlikely premise emerges one of the sharpest and most compelling spy thriller series of the modern era.
Read full series description
Set in a decaying London outpost where disgraced MI5 officers are sent to disappear professionally, the series follows a collection of damaged, ambitious, and deeply human characters who refuse to stay buried. At the center looms the unforgettable Jackson Lamb, a brilliant spymaster hidden beneath layers of cynicism, bad habits, and relentless insults. Around him gathers a rotating cast of sidelined operatives whose personal failures become the foundation for stories filled with danger, dark humor, and unexpected heroism.
What makes these novels stand apart is their remarkable balance of tones. Tense intelligence operations unfold alongside biting workplace satire. Bureaucratic infighting can be as dangerous as international conspiracies. The humor is razor-sharp, but beneath the wit lies a keen understanding of loneliness, loyalty, and the cost of living in the shadows. Every mission carries consequences, and every character, no matter how flawed, feels startlingly real.
The world of British espionage is portrayed not as a glamorous arena of gadgets and glamour, but as a landscape shaped by institutional rivalries, political maneuvering, and old secrets that refuse to remain buried. Cold War ghosts linger in the background, while contemporary threats constantly force the so-called failures of Slough House back into the field. Their greatest strength is often the fact that nobody expects them to succeed.
Over the years, the series has earned widespread acclaim for reinventing modern spy fiction, attracting a devoted readership and inspiring the highly successful television adaptation Slow Horses. Several entries have received major crime-writing honors, and the books have helped redefine what espionage novels can be in the twenty-first century.
Rich with suspense, dry British humor, political intrigue, and unforgettable character work, Slough House transforms a group of professional failures into some of the most fascinating figures in contemporary thriller fiction. It is a series where redemption is never guaranteed, competence often hides behind chaos, and the people written off by everyone else may be the only ones capable of saving the day.
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