THE SECRET DETECTIVE AGENCY (The Secret Detective Agency Book #1) by Helena Dixon is a historical cozy mystery introducing two British government agents working with clandestine agents being sent overseas in occupied Europe during 1941. A group of Miss Jane Treen’s agents are missing and turning up dead. Her boss assigns her to work with codebreaker Arthur Cilento when one of the missing agents ends up dead in a lake by his property in Devon. The blurb had me quickly picking up this book, but I ended up being disappointed.

The mystery starts out slowly, but I expect that in a new series due to setting up not only the mystery, but the new characters for the series, but it took too long for me. The mystery plot pace does pick up about halfway through the story, it does have a good resolution, and the author does a good job with her descriptions of the historic period settings, which is why I gave it a three-star rating. In the beginning of the story, the main characters are continually bouncing between the missing and dead agents’ code names and real names which is confusing, and I needed a cheat sheet to keep it straight. I usually love a strong, independent female protagonist, but Jane is a chain smoker with no consideration of others. Add to that Arthur has asthma and does not tell her to stop, which I found a major irritant that continually threw me out of the story. Overall, just not what I was hoping for.

Sometimes, you just need to read a good cozy mystery that you can curl up with and spend the day getting lost in. One that will transport you to a different time in a different place.

I’m here to tell you that this is that kind of book!

There’s trouble afoot against the backdrop of the Second World War, as agents that had been involved in a secret mission are disappearing, and later, turning up dead. Obviously not something that Jane Teen is keen on as she tries to work her way up through the intelligence world. When another agent is found dead on a remote English estate, she teams up with the owner of the property, also an intelligence officer, and the pair set off on a thrilling mystery.

This one has it all, folks. At least, everything I was looking for in historical English mystery that involves spies. There are mistaken, identities, twists, proper English butlers, gossiping, villagers, and of course, a one-eyed cat. There’s really not a lot more that you can ask for, is there? I thoroughly enjoyed the atmosphere of the author set up. It transported me right to the countryside of 1941 England. It was exactly the vacation I needed.

I also loved the two main characters in this book. I’m excited the author is starting this as a series because I can’t wait to read more about them, especially as we really just got to know them in this book and it feels like there’s a lot more to unravel about their personalities.

I look forward to the next book.

Jane Treen is a secret detective. One day a woman was found dead in a lake. Jane is called to investigate the case. However, Jane crosses paths with a shy Codebreaker named Arthur Cilento. Together, they team up to crack a coded diary and solve the case.

I thought that Jane was a very fun character! She was a cat fanatic and brought her cat with her everywhere she went. I also thought that she was very energetic. She was also very observant and is very passionate about crime! There were a few of her actions that I disagreed with. I also believed that she is selfish and judgmental at times. Nevertheless, Jane was a very quirky and enjoyable character!

I liked her relationship with Arthur. It took a lot for me to get invested in. I felt bad for Arthur because she did not take his health problems into consideration. However, they gradually grew to understand each other and were able to value the other’s talent. Therefore, their relationship grew on me, and I began to root for them. Their relationship eventually became one of the strongest aspects of this novel!

Overall, this novel is about secrets, war, and friendship. I liked all of the characters. I thought that they were very fun! I was also intrigued by the mystery and thought it was compelling! The novel is written in a humorous style! The novel also gave a good description of WWII, and thought that it was well-researched! Therefore, The Secret Detective Agency is a very light hearted and solid cozy mystery! I can’t wait to read the sequel, The Seaside Murders, soon! I am excited to revisit the characters again! I recommend this for fans of Maisie Dobbs, Mr. Churchill’s Secretary, and Her Royal Spyness!

Thank you NetGalley for the ARC.

I enjoy reading mysteries, and this was an enjoyable read. Set in the 1940s in London, and I appreciate the comparatively “slower” pace of the book compared to more “modern” writing. No need for modern technology of phones, just good old fashion crime solving.

January 1941. Miss Jane Treen is the overseer of Operation Exodus. She travelled to Half Moon Manor, the home of recently arrived code breaker Arthur Cilento as one of her agents has been found dead in his garden. That makes four of her six agents dead. Jane and Arthur join forces but where and who is the traitor, and the murderer as the deaths continue. Is there a network of spies working for the enemy.
An entertaining and well-written historical mystery with its two interesting and likeable main characters. Supported by a cast of varied personalities. A good start to this new series
An ARC was provided by the publisher via Netgalley in exchange for an honest review.

Thank you to Sarah Hardy and the publisher for issuing me with my review copy of the book and for inviting me to take part on the blog tour.

The Secret Detective Agency is a brand new series by Helena Dixon and set during the second world war in 1941. Miss Jane Treen works for a secret detective agency in London and is tasked with trying to find out the identity of a woman found dead in the lake of Arthur Cilento's stately home in Devon. Arthur also works for the government as a codebreaker and is about as different from Jane as anyone could possibly be! Jane is quite a forthright career women who loves coffee and cigarettes, along with her cat Marmaduke. Arthur likes the quiet life and has asthma and is back in Devon recuperating so is shocked when Miss Treen turns up on his doorstep.

Jane and Arthur are an interesting detective duo and I quite enjoyed learning a little about their past and lives. Jane is a character that you definitely learn to like, the more you read. She is quite prickly to start with but the time spent with the more compassionate Arthur, does seem to help thaw her a little bit especially as we learn more of the agents under her supervision have been found dead. Are the mysterious deaths linked - that is what Arthur and Jane are determined to find out.

The Secret Detective Agency is a really good introduction to a new series that I thoroughly enjoyed. The main characters are perfectly matched, each bringing their own unique talents to the investigation, that just makes them work well together along with help from Benson, Arthur's faithful butler. What I also really liked about this book was that the author didn't try to shoehorn the main characters into a romance. This may happen in the future but it was refreshing to read about the characters working relationship.

I'm looking forward to the second book in the series already (and have already signed up for the blog tour...!)

Highly enjoyable.

Jane is the epitome of a woman surviving and thriving in a male dominated world. WWII rages around the world and Jane is at the centre of the maelstrom of chaos. But when her network of spies are getting murdered, she is sent to Devon to investigate. With the help of super smart but very asthmatic Arthur and his ever helpful and efficient manservant, Benson, Jane will make short work of this mystery!

Jane is brash, brusque and used to bossing folk about and she is not the easiest person to like. You get glimpses of the private Jane - the protectiveness of her agents, the need to understand what happened and...avoiding her mother! She survives on coffee, the love of her cat and chaos. Arthur is a bit a nerdy MC and he's not the usual action-powered MMC - he is very cerebral but he can pull out some other skills when need be. They would never usually be the kind of partners either would want but they weirdly work well together.

The pacing was a wee bit slow in the first part of the book and it could have done with a bit more oomph but when the plot picks up it's a great wee murder mystery and moves along well. The red herrings and twists and turns pile up and our newly minted detectives are in the thick of it. I'm off to order book 2 to see where our detectives end up next!

An awesome historical mystery. I think Jane and Arthur made a great team. I'm so looking forward to more twisty, top secret mysteries from this pair. It was hard not to read in one sitting.

Murder mystery set in 1941 England during the war.

Miss Jane Treen works at Whitehall overseeing a cadre of secret agents for Brigadier Remington-Blythe. Hard and driven, she’s a chain smoker with a serious coffee addiction. She has no desire to go chasing after missing agents out in the country out of her comfort zone, but needs must when another of her agents goes dark after being hidden away for her own protection at a safe house. She travels to Half Moon Manor to work with codebreaker and puzzle solver Arthur Cilento. He has returned from a work mission for the War Office to find a dead body in the river by his home. Could this woman be Jane’s missing agent? Thus begins a reluctant partnership as the two try to trace a complicated organization of what might be traitors to the British government.

Let’s see — it took me quite a while to get invested in this time period and story. I didn’t immediately warm to the main characters of Jane (annoying) or Arthur (sickly) and the set up of them being forced to work together. The plot and the many different side characters seemed overly complicated and there were a lot of deaths as Jane and Arthur chased around with only the most flimsy of clues. I was definitely happy that the cat in this book had limited involvement and infrequent mention.

The plot was convoluted and the denouement seemed rushed after all the suspects couldn’t really be interrogated. I’ll have to reserve my thoughts about where this series might be going and if I will follow it after I read the second book. Not sure this unlikely pair will hold my interest if there is more repetition about Jane’s smoking and coffee and Arthur’s asthma. I surely hope no romance between them as she seems a determined spinster and him a confirmed bachelor. Of course there is also the faithful man servant who seems to be essential to the detecting and is always behind the scenes greasing the wheels.

I was able to listen to the audiobook while also following along in the e-book ARC, both provided by the publishers. The performance of the narrator, Kristin Atherton, was excellent. She did a fantastic job with all the voices and the transitions were seamless. Her dramatic flair made the book so much more enjoyable.

London 1941. Secret government worker Miss Jane Treen is addicted to coffee and cigarettes. Unfortunately, her new partner prefers tea and is asthmatic. ‘The Secret Detective Agency’ is first in a new series of cosy mysteries by Helena Dixon, author of the 1930s Kitty Underhay detective books.
Starting the first book of a new series is always a risky thing, it takes time to set up characters, back stories, context and as a result the pace can be slow. But I enjoy the Kitty books and the wartime setting of ‘The Secret Detective Agency’ is another plus. Miss Treen works for an unnamed government department running Operation Exodus, her team of secret agents assist the escape of double agents from Germany to the UK. But Jane’s agents are dying and when Polly Flinders is killed at a safe house in Devon, Jane is sent to investigate. Her boss, referred to as The Brigadier, teams her up with asthmatic code breaker Arthur Cilentro. They make an unlikely pairing, especially in the first half of the book. Chain-smoking Jane brings her long-haired cat Marmaduke with her to stay at Arthur’s house, Half Moon Manor. While the two investigators sniff around, asking questions, squabbling and sulking as they go, Arthur’s manservant Benson is the grown-up.
This is a story of wartime spies, treason, double dealing and multiple identities with rather confusing code names. By the time Miss Treen and Mr Cilentro have relaxed together enough to call each other Jane and Arthur, the death toll has increased. Fuelled by gossip in an isolated wartime village where everyone’s business is well-known, the two detectives realise that everyone is a suspect.
It is inevitable that the trio – don’t forget the indispensable Benson, who is always on hand with the essentials without which Jane and Arthur would simply fail – will morph into a team by the end of this novel. I expected Arthur to be quite bookish; he is, but also a fussy bachelor with severe breathing problems and a sharp analytical mind. I expected Jane to be an efficient professional young woman from London, responsible for a top secret mission; she is, but as a detective on the ground she can be naïve and not tight-lipped enough. She also ignores Arthur’s asthma. I got a bit fed up of her blowing smoke in Arthur’s direction and letting her cat into his sitting room. Thankfully as the story progresses, the two learn to appreciate each other’s skills and their relationship becomes less spiky.
More a cosy wartime mystery than cosy crime, this is a good start to a new series which offers something different. Irritations aside, this was a quick enjoyable read. I enjoyed the wartime espionage setting and the idea of a government detective agency specialising in crimes too secret for the police. It’s easy to have unreasonably high expectations of a new series and, looking back to my review of the first Kitty Underhay mystery ‘Murder at the Dolphin Hotel,’ it too was a 3* read for me. I’m now a firm fan of Kitty and Matt’s investigations in 1930s Dartmouth.
Coming soon is the second instalment of Jane and Arthur’s investigations, ‘The Seaside Murders.’ Hints about Jane’s family background, including a glamorous actress mother, are sure to become storylines in future novels.
Read more of my book reviews at http://www.sandradanby.com/book-reviews-a-z/

A Detective agency in Whitehall!

An unusual spinster, an asthmatic mathematical intellect and his quite efficient manservant end up working for a secret agency within Whitehall.
It’s 1941. Jane Treen has been running agents for an important behind the lines operation.
When the operation appears compromised they were withdrawn. Jane had installed one with a minder in a safe house in Devon only she knew about.
Unfortunately that agent has turned up dead in a local pond found by Arthur Cilento who’s just arrived home from his own highly secretive war work. He’s quite annoyed that the people his house had been rented out to were Jane’s agents and no one told him.
We have here a somewhat different trio of people who are determined to solve the dilemma. Then there’s the questions. Who else has been compromised? Who’s behind this?
I was very cross by the chain smoking Jane who seems to have no thought for the asthmatic Arthur, focused as she is on her own concerns.
The manservant, Bensen, as always, contributes calmly.
I admit it became obvious there was a link in the village but the how and why was interesting.
A very treadable, cozy murder mystery/spy plot

A Bookouture ARC via NetGalley.
Many thanks to the author and publisher.
(Opinions expressed in this review are completely my own.)

Jane and Arthur have worked on secret projects before, as their country is in the midst of the war. However, they do not care for the other. When Arthur finds a body in the water outside his new home, Jane is brought in because it turns out her team is being targeted. As the two work together, they have to try to solve what is happening, while maintaining secrecy. There is more to come for Jane and Arthur (and Arthur’s new status as a cat uncle).

I always thoroughly enjoy Helena Dixon's mysteries and was curious about this one that starts a new series.
Set during WWII, featuring a heroine quite brash and strong, it's an entertaining story full of potential.
I enjoyed the characters and the setting, some more twists in the mystery would have make it great.
A good start for a new series, cannot wait to read the next one
Highly recommended.
Many thanks to Bookouture for this ARC, all opinions are mine

I’m constantly scouring shelves for cozy mysteries, especially British ones if I can find them, and this one absolutely scratched that itch! The mystery itself was engaging enough to hold my attention, while the developing relationship between the two main characters warmed my heart and left me rooting for them. So excited for the sequel!

I received a copy of this book from the publisher, but all opinions are my own. The Secret Detective Agency is the first title from Helena Dixon, who is best known for her long running Miss Underhay cozy mysteries. This series is set in Britain during WWII and features Miss Jane Trent, who works in Whitehall and was responsible for running an operation that placed agents in occupied France. She is forced to travel to the home of Arthur Cilento, who although of a weak constitution, contributes to the war effort by using his codebreaking and puzzle-solving skills. After some time away, Arthur discovers a body near a pond on his land that turns out to be an agent that was part of Jane's operation. She's not the first agent to die after coming home causing a frantic effort to figure out who is killing agents and why.

I overall enjoyed this title, but did think it suffered a little from first book in the series syndrome with the need to provide background not directly related to the mystery. Arthur and Jane are both engaging characters and the fact the they initially are like oil and water makes for some fun interactions. I thought the mystery had some great twists and turns and am definitely looking forward to future titles.

London, 1941: Miss Jane Treen is at her desk when her top-secret government work is interrupted by an urgent call to Devon. A woman has been found dead in a lake in a place where she shouldn’t have been. Shy and handsome code-breaker Arthur Cilento didn’t expect to find a body when he moved into the house he’d recently inherited, he is bewildered by the arrival of the efficient Miss Treen and her cat Marmaduke. She bursts into his life unexpectedly, forcing him out of his comfort zone.
The start of a new series & the pace began slowly then increased throughout the book. I liked both Arthur & Jane but feel as though I’m still getting to know them, I did love how they interacted, Jane is an all guns blazing person whereas asthmatic Arthur takes things far more slowly. They are aided by Benson Arthur’s valet cum butler cum medic. The body count does rise throughout the book & Jane becomes increasingly worried about why agents she’s been supervising are being murdered. There were plenty of twists & turns as well as red herrings before the climax & I was kept guessing as to who the murderer was. A well written series starter. I half listened & have read the book & thoroughly enjoyed the audio version, the brilliant narrator certainly brough the book to life
I voluntarily read and reviewed a special copy of this book; all thoughts and opinions are my own

It's 1941 and England is at war. It's not much better at home, where Arthur Cilento finds a dead woman in the lake in his garden. Not just any woman, but a secret agent! Jane Treen, another secret agent, comes to investigate the murder of her colleague. It is not the first death she's investigating. It seems someone is after her whole team.

Together with Arthur, Jane starts interviewing all Arthur's acquaintances, which seems to be almost everyone in the village of Devon. Everyone is a suspect. And while doing so, more murders occur. Who is behind these murders and will Arthur and Jane be able to stop them?

The Secret Detective Agency by Helena Dixon is a lovely cozy crime novel. It's full of intrigue and plot twists. It's characters are divers, there's someone to like for everyone. Perhaps a little over the top from time to time. I especially liked Benson, Arthur's manservant, who seems to be not only equipped to take care of Arthur, but also ready for any top secret investigation.

The novel is high paced and easy to read. A great whodunnit novel. I had no idea who the culprit was until the very end, so that kept me going throughout the book. I just needed to know who the killer was!

The Secret Detective Agency is the first in a series with the same name. The second book, The Seaside Murders, will be published shortly. It is already waiting for me, so another review is coming soon as well!

I’m not, in general, a fan of books set during war. However, I love Helena Dixon’s Miss Underhay Mysteries, so I decided to give The Secret Detective Agency a chance. I’m glad I did.

I was immediately sucked into the story, and I was particularly interested by the fact that Arthur has asthma. I have a chronic illness myself, so it’s good to see main characters who are not 100% healthy or able bodied. Though of course it depends on how they’re portrayed. In this case, I felt it was very well done, neither calling for pity, nor using the “triumph over disability” trope that is so exhausting.

I liked both main characters, though Jane seemed rather uncaring about Arthur’s difficulties with his asthma to start with. However, as the book went on, she took more care, and I warmed to her more.

The mystery was an interesting one, I couldn’t tell who the culprit was until the reveal. It was very satisfying to follow along as Jane and Arthur solved the mystery.

Overall, I really enjoyed this story. In spite of being set during a war (one of my least favourite settings), it was fun to read and definitely remained in the cosy category. I’m looking forward to the second book in the series, The Seaside Murders.

I was given a copy of this book, my opinions are my own.

One of my WWII cozy mystery series is ending this summer and I enjoy Dixon's Miss Underhay series, so when I saw she had a new series coming out, I knew I had to try it.

I was hoping for a story that I could lose myself in for a few hours but I had real trouble getting into this story. It was a little slow and there was some over-explanation. I didn't really like Jane Treen or Arthur Cilento.

It also bothered me that the backmatter is 12% of the book. For a 264-page book that is about 30 pages - it seems a bit much to me. Since I got the ebook for free to review it was only mildly annoying but if I paid for it I might be more annoyed so I believe it is important for you to be aware of this.

The characters did grow on me some as the book progressed and I enjoyed the mystery. If you read my reviews very regularly, you know that I often start cozy mysteries in the middle of the series. I do that partly because I often dislike the first book in the series. My lukewarm reception of this series may be related to that. This series has potential and I look forward to the next book in the series.

My review will be published on Sunday at Girl Who Reads - https://www.girl-who-reads.com/2025/03/the-secret-detective-agency-by-helena.html

A cozy mystery set during war-time England in 1941, this is a fun read with delightful characters. What starts as a seemingly simple whodunit is soon to be revealed to be a complicated mystery. Jane Treen relies on the help of code-breaker Arthur, though neither are thrilled to be working together. Despite not seeing eye to eye, they make a fantastic team and have started to get close to the truth when they realize there's someone right on their heels who is willing to kill to keep their secrets. Time is running out, and the safety of our heroes and of England depends on them solving this case.
I loved Jane - it's always wonderful to see a strong, smart female lead and every female character in this book was interesting and strayed away from stereotypes. I liked that we see Jane and Arthur grow to respect each other without it diving into romance. The plot kept me guessing - I definitely didn't solve this before the reveal! I haven't read many books set in England during this era and liked all the details such as blackouts and the ration books - it really drew me into the story and gave it a realistic feel. I also liked Jane's cat and hope he shows up in future books. I will recommend this book to my friends.