Slow Horses Season 5 Episode 4: Coe Just Changed the Game — Here's What Went Down

Slow Horses usually treats disaster like a running joke, but Season 5, Episode 4 pushes that idea off a ladder. Literally. The episode is called 'Missiles,' and it turns a routine watch into an accidental, public death that blows a hole through Slough House and, potentially, MI5.

The setup

Season 5 is drawn from Mick Herron's fifth book, 'London Rules.' It premiered on Apple TV+ on September 24, 2025, with Episode 4 dropping October 15. In 'Missiles,' River Cartwright (Jack Lowden) and JK Coe (Tom Brooke) are assigned to shadow far-right politician Dennis Gimball (Christopher Villiers) at a nationalist rally. The brief is simple: keep eyes on the guy and stop anyone with bad intentions from getting near him.

How it goes sideways

River and Coe set up above the stage while Gimball leans into anti-MI5 rhetoric for the crowd below. Then Coe climbs down the scaffolding to help River, misses a step, and knocks a paint can loose. One sickening beat later: Gimball is on the ground, covered in pink paint, very much dead, and the crowd is processing that the danger came from above, not from the mob.

The show plays the moment with that signature deadpan-black-comedy tone, right up until it stops being funny. Coe brushes it off with a shruggy deadpan, and River immediately finds Gimball's pocket recorder still running. That audio is a live grenade: it captures everything and could spark a political meltdown while putting River and Coe at the center of it. What should have been a quiet watch turns into a PR nightmare for MI5.

Elsewhere, Shirley and Standish are fighting their own fires, but Coe and River's catastrophic 'oops' threatens to undo the slow reputational rehab Slough House has been cobbling together since Season 4.

Coe, under the microscope

Tom Brooke talked to TheWrap about where Coe's head is after that scene, and his read is... not comforting.

"I dont think Coe set out to kill anyone that night, but I dont think hes particularly disappointed that he gets to put another notch on his scorecard."

He calls Coe "a real psychopath" — someone who doesnt feel fear, remorse, or empathy. "The more people he kills, the happier he gets."

"Hes gone to the other end of the spectrum now. We havent found the thing that rattles him yet."

Brooke also says Coe plays especially well against River's permanent state of alarm: he enjoys sitting in the calm while someone else spins out. And even Jackson Lamb (Gary Oldman), who trusts no one as a rule, seems quietly comfortable with Coe's very specific brand of competence-in-chaos. The upshot: with one accidental killing, Coe jumps to the front of the pack as the show's most unsettling variable — a guy whose stillness is the loudest thing in the room.

Why this episode matters

'Missiles' is the show in microcosm: a job starts simple, the wrong detail goes wrong, and the fallout exposes a rot that is way bigger than one team or one office. Coe's non-reaction is the point — in Slough House, survival often looks like numbing yourself to consequences. And when Lamb inevitably pulls the threads on what really happened, it feels less like a freak accident and more like one more symptom of how broken the larger system is.

Season 5 rollout

• Episode 1 - 'Bad Dates' — Directed by Saul Metzstein; Written by Mick Herron, Will Smith — Released September 24, 2025
• Episode 2 - 'Incommunicado' — Directed by Saul Metzstein; Written by Mick Herron, Will Smith — Released October 1, 2025
• Episode 3 - 'Tall Tales' — Directed by Saul Metzstein; Written by Mick Herron, Will Smith — Released October 8, 2025
• Episode 4 - 'Missiles' — Directed by Saul Metzstein; Written by Mick Herron, Ed Docx — Released October 15, 2025
• Episode 5 - 'Circus' — Directed by Saul Metzstein; Written by Mick Herron, Will Smith — Releases October 22, 2025
• Episode 6 - 'Scars' — Directed by Saul Metzstein; Written by Mick Herron, Will Smith — Releases October 29, 2025

New episodes are rolling out weekly on Apple TV+. If the rest of the season keeps twisting accidents into consequences like this, Slough House is about to have a very bad month.