The Apple TV+ espionage series follows a group of MI5 rejects who instead of being fired are sent to purgatory – known as Slough House – under miserable boss Jackson Lamb (Gary Oldman).
Adapted from the Slough House series by Mick Herron, the third season is based on the book Real Tigers, the synopsis reading: "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."
The first trailer gives a taste of the action to come, with an MI5 team going rogue as they kidnap Catherine Standish (Saskia Reeves).
It's up to Jackson and the Slow Horses to band together, with a "reckoning" teased as part of the storyline.
As well as familiar faces, season 3 will see the additions of Gangs of London's Ṣọpẹ Dìrísù as the former head of security at the British embassy in Istanbul Sean Donovan, and Fantastic Beasts' Katherine Waterston as MI5 agent Alison Dunn.
Following season 3, a fourth outing was confirmed last year, which will continue to adapt the Slough House series.
Reflecting on Slow Horses' success last year, show boss James Hawes told Deadline: "What's astonishing is the positivity of the response, the amount that people have enjoyed and engaged with the series and also the global reach of the show.
"There are reviews from all over the world, and people seem to be getting the tone."
Slow Horses will premiere its third season on Apple TV+ on November 29, and drop new episodes every Friday throughout the month.
You Might Also Like