A crossword that’s tricky to crack, a hot cup of coffee… and hidden clues? Can Jane Treen work this mystery out?

England, 1942. Jane Treen is hot-footing it to Devon, having receivedan urgent message from her colleague and fellow sleuth, Arthur Cilento. He had been deeply worried for his mentor, crossword writer Professor Watkins. And the invitation he’s sent Jane is to the Professor’s funeral… he’s dead.

Arthur suspects foul play, but before they have time to fill in the blanks, their clues lead them into a secret vault nearby. Jane, fluffy ginger cat by her side, begins to connect the dots. But then another man is murdered, and she realises that Professor Watkins’ death is one piece in a much larger and deadlier game.

But who could be behind the untimely deaths? Could the professor’s beloved sister be responsible? Or a wealthy and influential benefactor and her assistant? And someone else close to the professor – also no stranger to compiling a crossword – seems to be increasingly cryptic too.

It’s clear that the killer isn’t playing by the book. And when the clue the professor left in the last crossword he wrote doesn’t help them to solve the crime, Jane and Arthur are back to square one and must think outside the box to crack the code. But just as they start to figure out what’s happening, they find themselves trapped, their lives at stake…

Can the duo solve the puzzle and escape before it’s too late?

If you love twisty crime novels and top-secret intrigue, then you will adore Helena Dixon’s utterly gripping cozy novel, perfect for fans of Agatha Christie, T.E. Kinsey and Verity Bright!

Published
October 15, 2026
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The Secret Detective Agency

The series

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Step into a world where secrets lurk in every shadow, and every clue leads to deeper mysteries. The Secret Detective Agency series, set in the 1940s, introduces readers to an unlikely but dynamic duo—Jane Treen, a government operative with a sharp mind and a quiet strength, and Arthur Cilento, a reserved but brilliant code-breaker. Together, they form a pair whose contrasting skills make them an unstoppable force in the world of clandestine investigations.

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The series begins with The Secret Detective Agency, where Jane and Arthur are thrust into the heart of a case that feels more like a puzzle than a typical investigation. As they delve into the secrets of a small English village, they uncover a network of hidden truths that will test their intellect and their bond. What starts as a quiet assignment quickly spirals into a trail of intrigue and danger, with every clue taking them deeper into a web of deception.

As the series unfolds, the duo faces new cases in different parts of England, each more baffling than the last. With each new adventure, they reveal more about themselves—Jane’s unyielding determination, Arthur’s quiet brilliance, and their growing respect for one another. Alongside the riveting mysteries, their developing relationship brings a fresh dynamic to the genre, blending suspense with tender moments.

The atmosphere of The Secret Detective Agency series is richly textured, transporting readers to the post-war England of the 1940s. Dixon's writing captures the era’s tensions and complexities, weaving them into the fabric of each story. With dark alleyways, coastal towns, and quiet villages as the backdrop, the series exudes a sense of mystery that mirrors its protagonists’ journeys.

Readers who enjoy a good puzzle, sharp wit, and intriguing characters will find themselves hooked from the very first book. The series expertly balances suspense with warmth, making it more than just a collection of mysteries—it’s a story about connection, perseverance, and uncovering hidden truths in a world full of secrets.

Perfect for fans of historical mysteries and detective duos, The Secret Detective Agency series invites you into a world of captivating investigations, unforgettable characters, and gripping twists that will keep you coming back for more.

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