Plot Synopsis

Based on Mick Herron's 2010 novel of the same name, SLOW HORSES is a six-episode espionage drama series that follows a team of British intelligence agents who serve in Slough House, a dumping ground department of MI5 due to their career-ending mistakes. Led by their brilliant but irascible leader, the notorious Jackson Lamb, they navigate the espionage world's smoke and mirrors to defend England from sinister forces. The story opens with River Cartwright being ousted from MI5, finding himself in a place worse than purgatory -- Slough House -- where he joins forces with Sid. The first two episodes of SLOW HORSES dropped on Friday, April 1, 2022 on Apple TV+, with a new installment debuting each Friday through April 29.

The sophomore season of SLOW HORSES premiered on Friday, December 2, 2022 on Apple TV+, as the streaming service released the first two episodes of the new season. A new installment drops each Friday through December 30. The second season is adapted from "Dead Lions," Mick Herron's second novel in the "Slow Horses" book series. Long-buried Cold War secrets emerge which threaten to bring carnage to the streets of London. When a liaison with Russian villains takes a fatal turn, our hapless heroes must overcome their individual failings and raise their spy game in a race to prevent a catastrophic incident.

Season 3 of SLOW HORSES, adapted from "Real Tigers," Mick Herron's third novel in the "Slow Horses" series, debuted on Wednesday, November 29, 2023 on Apple TV+, which released the first two episodes of the new season. In the six-episode third season, a romantic liaison in Istanbul threatens to expose a buried MI5 secret in London. When Jackson Lamb and his team of misfits are dragged into the fight, they find themselves caught in a conspiracy that threatens the future not just of Slough House but of MI5 itself. Sope Dirisu joins the cast as Sean Donovan, the former head of security at the British embassy in Istanbul. Season 3 also welcomes Katherine Waterston, who portrays Alison Dunn, an MI5 agent who uncovers a dark secret at the heart of the agency. A new installment dropped weekly through December 27.

On Wednesday, September 4, 2024, Apple TV+ kicked off the fourth season of SLOW HORSES by released the first episode. A new installment dropped weekly through October 9. Adapted from "Spook Street," the fourth novel in Mick Herron's "Slow Horses" series, Season 4 opens with a London bombing that puts Taverner under pressure. When River grows concerned for his grandfather, Louisa encourage him to go for a visit. Later, a naive agent makes a discovery about the Westacres bomber, while Lamb suspects David knows more than he's letting on. Hugo Weaving, Joanna Scanlan, Ruth Bradley, Tom Brooke, and James Callis join the cast for the fourth season.
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On Wednesday, October 9, 2024, Apple TV+ released "Hello Goodbye," the Season 4 finale of SLOW HORSES. Impossible decisions are faced and sacrifices are made.

SLOW HORSES has been renewed for a fifth season.