Slow Horses Season 3’s Biggest Book Change Ruined 1 Important Character Arc

Spoilers are ahead for Slow Horses season 3.

Slow Horses on Apple TV+ is a pretty faithful adaptation of the Slough House series of novels by Mick Herron, but one season 3 character change has huge implications for the show’s future. Ahead of season 4’s premiere, Slow Horses was renewed for a fifth outing, which means the series will need to plan ahead when it comes to its characters’ stories. Like the source material, Slow Horses is a spy thriller that centers on Slough House — the administrative purgatory for MI5 agents who made otherwise career-ending mistakes.

Led by Jackson Lamb (Gary Oldman), an incredibly rude and cruel intelligence vet, Slough House’s so-called “slow horses” somehow find themselves at the center of life-threatening schemes. River Cartwright (Jack Lowden), an up-and-coming agent who was tossed into Slough House’s ranks, and Deputy Director General of MI5 Diana Taverner (Kristin Scott Thomas) round out Slow Horses‘ core cast of characters. However, the show is also bolstered by an intriguing ensemble of supporting personalities, including Sean Donovan (Sope Dirisu) — a character who first appeared in Slow Horses season 3 (a.k.a. Real Tigers).

Donovan’s Story Is Completely Different In The Slough House Books

A former head of security at the British embassy in Istanbul, Turkey, Sean Donovan becomes a key character in the show’s third outing. While Donovan does appear in the Slough House novels, Slow Horses takes some liberties with his story — and said alterations may not be for the better. In the show, Donovan and fellow British intelligence operative Alison Dunn (Katherine Waterston) become lovers while stationed in Istanbul. When Donovan suspects Dunn of stealing classified information, he follows her on a city-wide chase. Eventually, Dunn hands off a file, dubbed Footprint, to a mysterious man.

Related

1 Missing Slow Horses Character Completely Changes Season 4’s Story

Based on the Slough House novels by Mick Herron, Apple TV+’s Slow Horses deviates from its source material, especially in regards to a key character.

Later, Donovan discovers that Dunn has been murdered. Seeking justice for Dunn’s death, Donovan appears to be the key antagonist in Slow Horses season 3. However, Donovan actually wants to leak Footprint — a file that contains incriminating information about MI5. In the book, Dunn’s death is completely different. The source material sees Donovan killing Alison Dunn in a drunk driving incident after his drink is spiked. Needless to say, Slow Horses paints Donovan’s grief over Dunn’s death in a much more clear-cut, sympathetic light by eliminating his (accidental) involvement in her murder.

What Donovan’s Story Change Means For Standish

What unfolds in Donovan’s Slow Horses season 3 story is very different to what happens in the books and has major implications for Catherine Standish (Saskia Reeves), MI5’s office administrator. A recovering alcoholic, Standish attends a post-work Alcoholics Anonymous (AA) meeting where she befriends Donovan, who is posing as a member of the group. Donovan ends up kidnapping Standish in order to have some leverage over MI5. While much of Slow Horses‘ first few episodes revolve around trying to secure Standish’s release, the kidnapped character ends up sympathizing with Donovan’s plight and helps him attain the Footprint file.

Related

7 Burning Questions Slow Horses Season 4 Needs To Answer

Apple TV+’s acclaimed spy series Slow Horses is preparing for its fourth season, and there are 7 burning questions that need be answered.

In the book’s version of events, Standish and Donovan have actual history, which sets up an incredibly different dynamic between the two. Real Tigers, the Slough House novel upon which season 3 is based, opens with Catherine Standish being accosted by Sean Donovan outside of Slough House. Not only is Donovan freshly out of prison — for a death he didn’t knowingly cause — he’s also Standish’s ex-lover. Donovan still uses Standish as leverage to secure the intel he’s looking for, but the characters’ history further complicates the story at hand and completely changes Standish’s Slow Horses character arc.