The Slow Horses showrunner explains the shock ending, the trailer for season 7 debuts

The Season 6 finale of Slow Horses is now available, with a shocking ending explained by new showrunner Gaby Chiappe in an interview. Additionally, Apple presented the first trailer for season 7.

Here’s what happened in Slow Horses’ surprise finale, plus the new season seven trailer

If you haven’t seen the Season 6 finale of Slow Horses yet, stop reading here.

**major spoilers ahead**

Slow Horses has been marked by a high number of character deaths this season.

This continued in the finale that just aired with the death of Emma Flyte at the hands of River’s father, Frank Harkness.

But in the episode’s final moments, there’s another character who also appears to die, and in a much more shocking way: River Cartwright.

It is not entirely clear, however, what caused the death. Here’s the official explanation from season six head writer and showrunner Gaby Chiappe (via Golden Derby):

Actually, the foundation is laid in episode 2, when Jim and Jane [the assassins played by Kyle Soller and MyAnna Buring] they come knocking on the door and River and Sid hide. You see Jim looking around and there’s a little bottle on the table. He looks around and sees the crowbar that River brought with him, and we have to assume that he paints it with what’s in the bottle, which, given that there have been nerve agent attacks elsewhere, is a Novichok attack.

We talked a lot about it. Will people know what it is and what is happening? It’s taken from the book, but in the book it’s left on the doorknob, which is a little different. It’s still the idea that something happened out of the corner of your eye, but you weren’t sure what it was. And the killer who planted it has been dead for some time now.

While Chiappe doesn’t technically confirm that River is dead, the season seven trailer certainly suggests that’s what happened.

Here’s the season seven trailer that airs at the end of the finale, courtesy of Apple TV News Hub on X: