Last Updated on April 22, 2026
For those of you who regularly visit my little site, you’ll know that there is no sub-genre of cozy mysteries that I won’t read.
I don’t mind if it’s gardening, baking, pensioners tracking down thieves, or some obscure Japanese locked room mystery.
One thing I have noticed, though, is the current trend of historical cozies. I’ve written about them before, but it seems that a lot of authors are harking back to a past where amateur sleuths relied solely on their wits and cunning, avoiding all of the tech tropes that so many of the more modern books rely on.
That brings me to The Secret Detective Agency by Helena Dixon, the first in her new series.
Some of you may already be familiar with her work, especially The Miss Underhay series, set in 1930s Devon.
It follows the astute and independent Kitty Underhay as she manages her family’s hotel, the Dolphin, and becomes entangled in various mysteries.
Anyway, Dixon has moved (for now) to a whole new world set in 1940s mid-war Britain, giving her plenty of juicy new spy-related stories to get stuck into.
So, how does the first one fare? Should you rush out to read it, or should you plump for something different?
Meet Jane Treen
Miss Jane Treen works in Whitehall during the war. Her job is to co-ordinate various overseas operations, planting spies in order to help Britain gain a tactical advantage.
During one particular operation, Exodus, seven of her operatives appear to have their covers blown, resulting in one of their deaths.
The operatives, upon returning to England, are then bumped off one by one, including Kate Trevellian, whose body is found at Half Moon Manor in Devon.
Half Moon Manor also happens to be where she was hiding out, unbeknownst to the homeowner, Arthur Cilento.
Arthur had rented his home out while he himself worked as a code breaker, having such severe asthma that it prevented him from fighting on the frontlines.
Jane Treen is then tasked with heading to Half Moon Manor to work with Arthur to figure out who murdered Kate and uncover the plot to kill off the remaining Operation Exodus spies.
That’s basically the crux of the story in a nutshell. The problem is that the plotting is so overly complicated that it was almost impossible to figure that out until a good way into the book!
Contrasting Detectives
I want to preface this by saying that I fully appreciate what Dixon was trying to do with The Secret Detective Agency.
The idea is that by pairing up such contrasting detectives – one brash and the other relatively quiet, we could get a more dynamic partnership.
It is a sound premise, and it would have worked really well if Jane Treen hadn’t been so inherently unlikeable.
Let me explain. Jane Treen is basically a chain smoker. That’s fine, it’s 1941, lot of people, especially in incredibly stressful situations, smoke. No judgment.
However, we’ve already been told that Arthur suffers from debilitating asthma, and yet Ms Treen smokes like a chimney in his company.
Aside from the utter lack of consideration on her part, even worse is that this fact is hammered home to us every single chance the author gets. And I mean Every. Single. Time.
If Jane Treen even thinks about having a cigarette, we know about it. It must be mentioned at least fifty times, if not more, in the book.
It got so distracting and so infuriating that it was like an itch you can never scratch.
I have no idea what the reasoning behind this was other than to make Treen deeply unappealing and to highlight Cilento’s patience and gentlemanly behavior somehow, as he never once said anything to her about it.
For me, it didn’t work. What should have been a clever story about two intrepid detectives moving from clue to clue as they closed in on the culprit just became a story that frustrated me.
And that was such a massive shame because the plot is really clever. The setting is excellent, the characters all bring something different to the table, and the linear method of one clue leading to another is solid.
Is It Worth Reading?
I know that other readers have loved this book for all the good reasons I mentioned above. Others, however, encountered the same character issues that I did, so it looks like the opinion is split.
If you can get over Ms Treen’s complete lack of consideration – she does refrain once from lighting up when she sees Arthur wheezing – and the fact that Arthur seems to just get dragged along, then this has all the makings of a good series.
Time will tell if they evolve, as there is already a second book in the works. It’s called The Seaside Murders and is due out in late 2025.
I’d love to know if any of you have read The Secret Detective Agency and what your thoughts are, so leave a comment below if you would like to.
I know that what bothers me sometimes really doesn’t bother anybody else – just ask my other half!
