The Thirty-Second Book of 2026: The Secret Hours, by Mick Herron

Note: I’m a little behind in getting out reviews because I spent the weekend at Write On The Sound, a lovely little writer’s conference in Edmonds, Washington, just north of Seattle and yes, right on Puget Sound. While there, I took in a presentation called The Amateur Sleuth’s Guide to Writing Mysteries, Thrillers and Suspense by Seattle-area author Glen Erik Hamilton. Glen is a fellow Slow Horses fan, and we were able to geek out a little about the time he met Mick Herron and how the way Apple TV portrays Jackson Lamb is more human and approachable than in the books, because when you have a talent like Gary Oldman you want him to be on the screen as much as possible...kinda the opposite of the Lamb in the books.

Slow Horses aren’t the only books Mick Herron has written. Before he took up espionage, he was a crime writer, with four books in the Zoë Bohm universe, and others besides.

But he seems to like the Slow Horses world, which has probably given him the biggest success, and he’s written a few things in the Slow Horses universe that aren’t actually Slow Horses books. One of these is The Secret Hours.

The story is billed as exploring the background of a few of the Slow Horses characters, but he tries to make you work a little to figure out who is who, though the closer we get to the end it gets easier and easier to guess.

The story starts with a former MI5 asset in trouble. The opening chapter is certainly exciting…but then the topic and the character are dropped until later in the story. The asset in trouble, now living in the UK, has obviously gone through a name change over the years. But even when we get into the meat of the story, framed by an inquiry into operations of MI5 called Monochrome, everyone is called by their “work name,” the names they operated under while working for British Intelligence in Berlin in the early 1990s, after the fall of the Berlin Wall and reunification of Germany. No one goes by names fans would recognize, though Herron certainly leaves enough clues that no one should have difficulty figuring out who’s who.

After the first chapter, I found the remainder of the first third or so of the book a bit slow. There’s too much discussion of process and procedure, how an independent inquiry like Monochrome is set up and managed, and maybe a bit too much into the thoughts and backgrounds of the two civil servants who have been “seconded” from their regular jobs to this one.

Things pick up, though, when Montgomery Kyle, the younger of the two civil servants, finds a secret file from the MI5 archives in his shopping cart. It’s the first substantial information Monochrome has received in over a year. It’s perfectly appropriate for Monochrome to have it…it’s only the way they got it that is questionable.

Based on information in the file, Monochrome calls in a long-time Regents Park staffer, one well-known to Slow Horses readers, to testify about their work in Berlin at the dawn of their career. Their ostensible assignment is to bring the office’s accounts into order, but David Cartwright, the shadowy power behind the scenes of the Park in those years, has given them a second set of orders: get close to certain Berlin staffers and find out if everything as above-board as it could be.

The story becomes an intimate account of life in Berlin in the years after the fall of the Berlin Wall, of spies who no longer have an enemy to spy on but lots of scores to settle. And when the witness’s testimony to Monochrome is complete, the identity of the asset in trouble becomes clear, as do the current names of the other players in the story.

Though The Secret Hours seems in danger of losing steam early, it’s certainly worth plowing through to get to the good parts. It tells us a bit about how certain people we know from Slow Horses came to be what and who they are, and that makes for a satisfying book.