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Kat and Lock #4
Body of Lies
Not yet published
Expected 21 May 26The brand-new thriller featuring DCS Kat Frank and AIDE Lock from the award-winning and
Sunday Times
bestselling author of
In the Blink of an Eye
.
Human suspicion. AI manipulation.
Who can you trust when truth has no meaning?
DCS Kat Frank returns to work at the Future Policing Unit after a tragic loss, only to find herself thrust into a new high-profile case. On the night of Halloween a local MP is found murdered, with a taunting message written in binary code that seems to target Kat Catch me if you can.
The victim’s anti-AI sentiments suggest a political motive, and as Kat investigates with her partner AIDE Lock – the world’s first AI detective – she finds herself once again battling her own prejudices about the technological future he represents. But when a cyberattack takes out the National Grid, Kat and Lock have to race against the clock to track down the hacker before thousands die.
Tangled in a web of suspicion and deception, Kat must choose who and what to believe when the truth seems to defy both instinct and logic.
Can she set aside her old doubts and put her faith in her AI partner one last time?
Or will this case send Lock down a path she just can’t follow – a path that will leave humanity behind for good?
PRAISE FOR JO
'Terrifyingly timely and provocative' VAL McDERMID
'The most original crime novel you'll read this year' CLARE MACKINTOSH
'Just brilliant!' LISA JEWELL
'Sharp, perceptive writing and a brilliant new take on the detective duo' T. M. LOGAN
'Everything you could hope for in a heartbreaking, intelligent, deftly plotted and so original' FIONA CUMMINS
'A fresh take on the buddy-buddy cop trope . . . Provocative and compelling' VASEEM KHAN
'Wildly original, heartfelt, funny, and properly thrilling. Take a bow, Jo Callaghan' CHRIS WHITAKER
Human suspicion. AI manipulation.
Who can you trust when truth has no meaning?
DCS Kat Frank returns to work at the Future Policing Unit after a tragic loss, only to find herself thrust into a new high-profile case. On the night of Halloween a local MP is found murdered, with a taunting message written in binary code that seems to target Kat Catch me if you can.
The victim’s anti-AI sentiments suggest a political motive, and as Kat investigates with her partner AIDE Lock – the world’s first AI detective – she finds herself once again battling her own prejudices about the technological future he represents. But when a cyberattack takes out the National Grid, Kat and Lock have to race against the clock to track down the hacker before thousands die.
Tangled in a web of suspicion and deception, Kat must choose who and what to believe when the truth seems to defy both instinct and logic.
Can she set aside her old doubts and put her faith in her AI partner one last time?
Or will this case send Lock down a path she just can’t follow – a path that will leave humanity behind for good?
PRAISE FOR JO
'Terrifyingly timely and provocative' VAL McDERMID
'The most original crime novel you'll read this year' CLARE MACKINTOSH
'Just brilliant!' LISA JEWELL
'Sharp, perceptive writing and a brilliant new take on the detective duo' T. M. LOGAN
'Everything you could hope for in a heartbreaking, intelligent, deftly plotted and so original' FIONA CUMMINS
'A fresh take on the buddy-buddy cop trope . . . Provocative and compelling' VASEEM KHAN
'Wildly original, heartfelt, funny, and properly thrilling. Take a bow, Jo Callaghan' CHRIS WHITAKER
- GenresThrillerProcedural
448 pages, Kindle Edition
Expected publication May 21, 2026
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Displaying 1 - 30 of 40 reviews
January 15, 2026
What a way to end the series!
Review of advance copy received from Publisher
There are no spoilers here. I always make sure not to include any but as this is the final book in the series I wanted to make that explicit.
Body of Lies picks up from the events of that explosive ending to Human Remains. This is a unique police procedural series that is absolutely worth your time. I personally was foolish and ignored my friends’ praises of Callaghan’s debut In the Blink of an Eye. They told me I would love it, but being aware one of the detectives was AI, I assumed I would not get on with it. I see this criticism a lot, so if you are in the same boat then please know I wholeheartedly recommend this series and hold my hands up that I was very, very wrong.
Yes, there is an AI element to the series, but it’s done incredibly well and it’s about so much more than that. Kat is such a well-written character, so believably human and incredibly relatable. Heck, I even love (love to hate or hate to love?) Lock.
Body of Lies features DCS Kat Frank and her holographic assistant AIDE Lock as they investigate the murder of a local MP. At the scene, they uncover a hidden message that seems to be targeting them. The series feels timely and resonant, in real life earlier this year CrimeOwl AI launched to help investigators process thousands of files in minutes, making it easier to connect evidence, uncover hidden patterns and generate new leads. It’s no surprise that Callaghan pre-empted this in her novels, as she has a background as a senior strategist researching the future impact of AI on the workforce.
Throughout the series there has been ambiguity surrounding Lock. Is it possible for the AI to have its own alternative motives and do a Skynet? There’s a knife-edge uncertainty throughout and I loved the resulting tension.
As mentioned I won’t go into too much more of the plot to avoid spoilers. I will say that there was a part that gave me Fight Club vibes and that the ending was superb. What a ride this masterpiece series has been.
Thank you to Simon & Schuster for the proof copy.
Body of Lies picks up from the events of that explosive ending to Human Remains. This is a unique police procedural series that is absolutely worth your time. I personally was foolish and ignored my friends’ praises of Callaghan’s debut In the Blink of an Eye. They told me I would love it, but being aware one of the detectives was AI, I assumed I would not get on with it. I see this criticism a lot, so if you are in the same boat then please know I wholeheartedly recommend this series and hold my hands up that I was very, very wrong.
Yes, there is an AI element to the series, but it’s done incredibly well and it’s about so much more than that. Kat is such a well-written character, so believably human and incredibly relatable. Heck, I even love (love to hate or hate to love?) Lock.
Body of Lies features DCS Kat Frank and her holographic assistant AIDE Lock as they investigate the murder of a local MP. At the scene, they uncover a hidden message that seems to be targeting them. The series feels timely and resonant, in real life earlier this year CrimeOwl AI launched to help investigators process thousands of files in minutes, making it easier to connect evidence, uncover hidden patterns and generate new leads. It’s no surprise that Callaghan pre-empted this in her novels, as she has a background as a senior strategist researching the future impact of AI on the workforce.
Throughout the series there has been ambiguity surrounding Lock. Is it possible for the AI to have its own alternative motives and do a Skynet? There’s a knife-edge uncertainty throughout and I loved the resulting tension.
As mentioned I won’t go into too much more of the plot to avoid spoilers. I will say that there was a part that gave me Fight Club vibes and that the ending was superb. What a ride this masterpiece series has been.
Thank you to Simon & Schuster for the proof copy.
Review of advance copy
Book Review 📚
Body of Lies - Jo Callaghan
Rating 5 Stars ! ⭐️⭐️⭐️⭐️⭐️
First of all thank you to bestie Michaela for very kindly providing me with a copy of this proof because it made my whole year 🙏🤣
However this book, where do I even begin ?! It was never going to be less than five stars so let's get that bit out of the way, absolutely amazing 👏
We follow Kat, Lock and the rest of the team whilst they are trying to solve the murder of a local MP which occurs on the night of Halloween, also during a power cut. I'm not going to say anymore about the plot as I obviously don't want to spoil anything !
I am sad that the series has come to an end as I love every single one of the characters so much and that just shows how amazing Jo writes ! However I will say believe it's been concluded fabulously and I wouldn't have wanted it any other way.
I don't know what to do now it's all over, I guess when the audiobook is released later this year I'll just have to do a re-read of the whole series ?! 💁♀️
Body of Lies - Jo Callaghan
Rating 5 Stars ! ⭐️⭐️⭐️⭐️⭐️
First of all thank you to bestie Michaela for very kindly providing me with a copy of this proof because it made my whole year 🙏🤣
However this book, where do I even begin ?! It was never going to be less than five stars so let's get that bit out of the way, absolutely amazing 👏
We follow Kat, Lock and the rest of the team whilst they are trying to solve the murder of a local MP which occurs on the night of Halloween, also during a power cut. I'm not going to say anymore about the plot as I obviously don't want to spoil anything !
I am sad that the series has come to an end as I love every single one of the characters so much and that just shows how amazing Jo writes ! However I will say believe it's been concluded fabulously and I wouldn't have wanted it any other way.
I don't know what to do now it's all over, I guess when the audiobook is released later this year I'll just have to do a re-read of the whole series ?! 💁♀️
May 13, 2026
Guys, I’m bereft and mind-blown all in equal measure. I have just finished Jo Callaghan’s Kat & Lock series with the final instalment ‘Body Of Lies’ and I am NOT OK. What I have just experienced is nothing short of masterful. I have experienced every range of human emotion throughout this series, but especially with this book, which serves as the finale to close out this fantastic series.
It’s hard to believe that I only joined the ranks of the CallaFANS fairly recently, but I have devoured four books now in less than a month and I have become so emotionally invested with Kat & Lock that it’s almost unhealthy at this point. This series is so exquisitely crafted and everything has been leading up to this point. I can’t say too much about this book without spoiling anything, so I’m trying to do my very best to review ‘Body Of Lies’ without revealing anything and it’s HARD! What I will say, however, is that it’s hard to build up a series and close it so that everybody is satisfied, but I think I can say with some confidence that people are going to be sad. Yes, but I think people are going to be really satisfied and mind-blown by this explosive finale to a much-loved series.
I am going to miss Kat & Lock so much. They have brought me so much joy. I had tears steaming down my face reading the last chapters and I just know that this is going to be a series that stays with me for a long time to come. What Jo has created with this series and these characters in particular is phenomenal, and I cannot wait to see what she writes next. ‘Body Of Lies’ is out next week and I want to say a huge thank you to Jo for kindly sending me an early copy for review.
PS: This was the hardest spoiler-free review I think I’ve ever had to write 🤣🤭
It’s hard to believe that I only joined the ranks of the CallaFANS fairly recently, but I have devoured four books now in less than a month and I have become so emotionally invested with Kat & Lock that it’s almost unhealthy at this point. This series is so exquisitely crafted and everything has been leading up to this point. I can’t say too much about this book without spoiling anything, so I’m trying to do my very best to review ‘Body Of Lies’ without revealing anything and it’s HARD! What I will say, however, is that it’s hard to build up a series and close it so that everybody is satisfied, but I think I can say with some confidence that people are going to be sad. Yes, but I think people are going to be really satisfied and mind-blown by this explosive finale to a much-loved series.
I am going to miss Kat & Lock so much. They have brought me so much joy. I had tears steaming down my face reading the last chapters and I just know that this is going to be a series that stays with me for a long time to come. What Jo has created with this series and these characters in particular is phenomenal, and I cannot wait to see what she writes next. ‘Body Of Lies’ is out next week and I want to say a huge thank you to Jo for kindly sending me an early copy for review.
PS: This was the hardest spoiler-free review I think I’ve ever had to write 🤣🤭
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May 4, 2026Reviewing for blog tour. I've loved this series and sad this is the final one.
Review of advance copy received from Publisher
⭐️ 5 ⭐️
Body of Lies is the fourth and final book (sob) in the Kat and Lock crime thriller series. If you haven’t read any of the other books, I can’t recommend them highly enough. They can all be read as standalones, but getting to know the characters’ backstories is all part of the fun.
Body of Lies is well written; the story is engaging and highly entertaining, but for me, the stars of the show are definitely the characters. From the first book, Kat and Lock quickly became one of my favourite duos. The pairing of DCS Kat and AI detective Lock is a match made in heaven; the humour, camaraderie, rapport and banter between the whole team are a joy, and reading it was like visiting old friends.
I absolutely loved it, and although I’m gutted that this is the end for the dynamic duo, the ending was spot on (and made me cry). What an amazing series (I still say it would make fantastic TV).
I can’t wait to see what Jo Callaghan’s got up her sleeve next. Put it (and the other three) on your list; you’ll thank me later!
Many thanks to the publisher for the proof copy, in exchange for an honest, unbiased review.
Body of Lies is the fourth and final book (sob) in the Kat and Lock crime thriller series. If you haven’t read any of the other books, I can’t recommend them highly enough. They can all be read as standalones, but getting to know the characters’ backstories is all part of the fun.
Body of Lies is well written; the story is engaging and highly entertaining, but for me, the stars of the show are definitely the characters. From the first book, Kat and Lock quickly became one of my favourite duos. The pairing of DCS Kat and AI detective Lock is a match made in heaven; the humour, camaraderie, rapport and banter between the whole team are a joy, and reading it was like visiting old friends.
I absolutely loved it, and although I’m gutted that this is the end for the dynamic duo, the ending was spot on (and made me cry). What an amazing series (I still say it would make fantastic TV).
I can’t wait to see what Jo Callaghan’s got up her sleeve next. Put it (and the other three) on your list; you’ll thank me later!
Many thanks to the publisher for the proof copy, in exchange for an honest, unbiased review.
Review of advance copy
This is the 4th and final book in this series and continues directly on from the events at the end of the previous so you really do need to start from book and and read in order or things might not make sense...!
As already mentioned, this book picks up a little while after Human Remains finished. Kat and her team are still reeling from their devastating loss. An event that AIDE Lock firmly believes that wouldn't have happened had he a physical body. Something he is really gunning for. The event happened at Kat's home and we catch up with her just as she is returning home for the first time since said event. A home that now doesn't feel much like it, mostly due to the refurb, but that also means that there are more links to her late husband that have been lost to her. But, as well as being wary of the place she used to feel safe, to add to her woes, she has only just arrived when the lights all go out. Scaring her massively, until Lock reassures her that it's just a power cut and, through his hologram, provides some light. Long story short and the power cut wasn't a fault, more an attack and, during it, the new local MP was brutally murdered and displayed in the stocks. An MP who just happens to be very anti AI. With a message for Kat and Lock in her pocket.
Oh, and did I mention it was Halloween...!
And that's all I am saying as, if you have read the previous books, and you have, haven't you? You'll know exactly what you are letting yourself in for with this one. In fact, after the way book 4 ended, you'll have probably either begged, borrowed or stole to get your grubby mitts on this book, or you will have pre-ordered already and are waiting for the time to tick over to release date... In fact, I am not sure who is left reading this review...
So... this series for me has had its ups and downs and has challenged me along the way. I'm not a fan of AI and my limited experience of it has had mixed results. From some really great insight, to talking absolute rot, through guessing, and finally, and this has happened more than expected, actually being gas lit. One AI actually argued with me, trying to convince me that they were right (they weren't) and I was wrong (I wasn't). But that really scared me. Even though we were just talking about sports. Especially as my boss currently uses "just put it through AI" as an answer to pretty much everything these days... And couple that with the damage AI is doing to books, narration, films, art, even the stage, etc... It's only a matter of time before this all becomes fact. And don't get me started about how AI is progressing faster than legislation can catch up...
So yeah, this book, the ongoing story has in equal measure annoyed me, irked me, surprised me, and I have avidly followed Lock's development with both hope and trepidation. Fearful and excited for what the future could possibly bring. I've also loved his partnership with Kat who has been exactly the right person to both progress and challenge him. And the case they are embroiled in here takes it up a notch as they pretty much go national with what is happening...
And then there's the ending. I never thought we would ever go there. Not a clue. Didn't see that coming and actually feel quite bereft now the series has finished. Me and Lock have had our ups and downs but now the series is over, I think I'm really going to miss him...
Although... On the flip side, I also can't help wondering what the author will deliver up for her next book, and I am rather excited to find out...
As already mentioned, this book picks up a little while after Human Remains finished. Kat and her team are still reeling from their devastating loss. An event that AIDE Lock firmly believes that wouldn't have happened had he a physical body. Something he is really gunning for. The event happened at Kat's home and we catch up with her just as she is returning home for the first time since said event. A home that now doesn't feel much like it, mostly due to the refurb, but that also means that there are more links to her late husband that have been lost to her. But, as well as being wary of the place she used to feel safe, to add to her woes, she has only just arrived when the lights all go out. Scaring her massively, until Lock reassures her that it's just a power cut and, through his hologram, provides some light. Long story short and the power cut wasn't a fault, more an attack and, during it, the new local MP was brutally murdered and displayed in the stocks. An MP who just happens to be very anti AI. With a message for Kat and Lock in her pocket.
Oh, and did I mention it was Halloween...!
And that's all I am saying as, if you have read the previous books, and you have, haven't you? You'll know exactly what you are letting yourself in for with this one. In fact, after the way book 4 ended, you'll have probably either begged, borrowed or stole to get your grubby mitts on this book, or you will have pre-ordered already and are waiting for the time to tick over to release date... In fact, I am not sure who is left reading this review...
So... this series for me has had its ups and downs and has challenged me along the way. I'm not a fan of AI and my limited experience of it has had mixed results. From some really great insight, to talking absolute rot, through guessing, and finally, and this has happened more than expected, actually being gas lit. One AI actually argued with me, trying to convince me that they were right (they weren't) and I was wrong (I wasn't). But that really scared me. Even though we were just talking about sports. Especially as my boss currently uses "just put it through AI" as an answer to pretty much everything these days... And couple that with the damage AI is doing to books, narration, films, art, even the stage, etc... It's only a matter of time before this all becomes fact. And don't get me started about how AI is progressing faster than legislation can catch up...
So yeah, this book, the ongoing story has in equal measure annoyed me, irked me, surprised me, and I have avidly followed Lock's development with both hope and trepidation. Fearful and excited for what the future could possibly bring. I've also loved his partnership with Kat who has been exactly the right person to both progress and challenge him. And the case they are embroiled in here takes it up a notch as they pretty much go national with what is happening...
And then there's the ending. I never thought we would ever go there. Not a clue. Didn't see that coming and actually feel quite bereft now the series has finished. Me and Lock have had our ups and downs but now the series is over, I think I'm really going to miss him...
Although... On the flip side, I also can't help wondering what the author will deliver up for her next book, and I am rather excited to find out...
January 11, 2026
Was it my age, the raging hormones, or just how well written this book is, how heavily the ending lands, that had me in tears? I suspect somewhere in a mix of all three but I warn you now. If you are a fan of the books, if you have any love for Kat and her most unusual of partners in crime fighting, Lock, then do not underestimate how much reading this book is going to hurt, becuase it is. So, so sad that this is the final book, but if the series has to end, what a way to go.
I have out off writing a review of this book, not because I didn't enjoy it, because I absolutely, categorically did. It is simply because I don;t know if I have the words to do it justice when all I want to do is shout about all the "whaaaaat?", "OMG!" and "what the heck did you just do" that really do fall into spoiler territory. I can't and I won't just still. All of those and more. If you thought the ending of the previous book was shocking, just you wait. This book. So topical, so powerful. So absolutely brilliant.
I really am trying to avoid spoilers so this will be necessarily vague. Needless to say, we find Kat still reeling from what happened in the Human Remains, and trying to come to terms with what she believed she heard and saw in those dying pages. It's a big deal, as is moving back into her home for the first time since that fateful day that changed everything. I like how the author has portrayed this really clear emotional struggle that Kat goes through, wanting to rely on Lock but fearful of what has passed and what might come to be. It's not long before she has a very welcome distraction though in the form of the discovery of a body in her own home town, that of someone very critical of evolving AI capabilities and especially their place in the Police force. Not really hard to guess how quickly this is linked back to Kat and Lock or even how quickly this could all well go south ...
Which, ironically, it does. To Westminster and series of events that really do form the heart of this book. And that is where my recap ends and you have to read the book to get the rest for yourself. Whilst the murder investigation is equal parts intriguing and frustrating, and the list of potential suspects both finite and wide reaching given the victims status in the community, it is in the scenes in the latter part of the book where the story really picks up pace. Where Jo Callaghan plays an absolute blinder. I was both suckered in and also sceptical. I wanted to believe in the characters I have come to love even as all the evidence pointed wholly against them. This is very much a ticking clock case with huge ramifications if Kat cannot solve it, and also one in which she is going to have to rely on her own wits in order to come good. There is tension and intensity in every scene, and I had so many thoughts, doubts even, swirling in my mind at one time that I couldn't have looked away or put the book down even if I wanted to. Which I did not.
This book is so topical, generating such important questions for discussion that it probably the kind of thing that should be on a school English Lit syllabus. I had barely finished reading when the whole topic of AI and whether or not it would ever be capable of conscious decision making was on the morning news. And with all the recent take of AI being abused for the purpose of abusing others, the ethical, as well as very real environmental concerns of using AI is not only something brought to the fore in this book, but something I am ever more conscious now in the real world. And that is a powerful thing to pull from a book that is exceedingly thought provoking entertainment.
The ending of the book is shocking, heartbreaking even. I nearly dislocated my jaw, it fell so fast. And then the tears - emotional not pain derived - that were almost inevitable from the very first page of the book. You know you are heading towards an ending when you start reading a 'last in the series', but I never expected it to be this hard hitting or poignant. I like the final touches of the book, care taken with her characters right to the very end, but by golly. I am going to miss this series, and, in the (sort of) words of Dorothy Gale, 'I think I'll miss you most of all, Lock'. A fitting, if sad finale and completely recommended.
I have out off writing a review of this book, not because I didn't enjoy it, because I absolutely, categorically did. It is simply because I don;t know if I have the words to do it justice when all I want to do is shout about all the "whaaaaat?", "OMG!" and "what the heck did you just do" that really do fall into spoiler territory. I can't and I won't just still. All of those and more. If you thought the ending of the previous book was shocking, just you wait. This book. So topical, so powerful. So absolutely brilliant.
I really am trying to avoid spoilers so this will be necessarily vague. Needless to say, we find Kat still reeling from what happened in the Human Remains, and trying to come to terms with what she believed she heard and saw in those dying pages. It's a big deal, as is moving back into her home for the first time since that fateful day that changed everything. I like how the author has portrayed this really clear emotional struggle that Kat goes through, wanting to rely on Lock but fearful of what has passed and what might come to be. It's not long before she has a very welcome distraction though in the form of the discovery of a body in her own home town, that of someone very critical of evolving AI capabilities and especially their place in the Police force. Not really hard to guess how quickly this is linked back to Kat and Lock or even how quickly this could all well go south ...
Which, ironically, it does. To Westminster and series of events that really do form the heart of this book. And that is where my recap ends and you have to read the book to get the rest for yourself. Whilst the murder investigation is equal parts intriguing and frustrating, and the list of potential suspects both finite and wide reaching given the victims status in the community, it is in the scenes in the latter part of the book where the story really picks up pace. Where Jo Callaghan plays an absolute blinder. I was both suckered in and also sceptical. I wanted to believe in the characters I have come to love even as all the evidence pointed wholly against them. This is very much a ticking clock case with huge ramifications if Kat cannot solve it, and also one in which she is going to have to rely on her own wits in order to come good. There is tension and intensity in every scene, and I had so many thoughts, doubts even, swirling in my mind at one time that I couldn't have looked away or put the book down even if I wanted to. Which I did not.
This book is so topical, generating such important questions for discussion that it probably the kind of thing that should be on a school English Lit syllabus. I had barely finished reading when the whole topic of AI and whether or not it would ever be capable of conscious decision making was on the morning news. And with all the recent take of AI being abused for the purpose of abusing others, the ethical, as well as very real environmental concerns of using AI is not only something brought to the fore in this book, but something I am ever more conscious now in the real world. And that is a powerful thing to pull from a book that is exceedingly thought provoking entertainment.
The ending of the book is shocking, heartbreaking even. I nearly dislocated my jaw, it fell so fast. And then the tears - emotional not pain derived - that were almost inevitable from the very first page of the book. You know you are heading towards an ending when you start reading a 'last in the series', but I never expected it to be this hard hitting or poignant. I like the final touches of the book, care taken with her characters right to the very end, but by golly. I am going to miss this series, and, in the (sort of) words of Dorothy Gale, 'I think I'll miss you most of all, Lock'. A fitting, if sad finale and completely recommended.
Review of advance copy received from Publisher
Kat’s got a new case on Hallowe’en.
I am at a complete loss to know how to review Body of Lies. I thought it was utterly fabulous. There are so many aspects to Jo Callaghan’s insightful writing that each book rewards multiple reads and Body of Lies is no exception.
Obviously plot is of supreme importance and in Body of Lies there is a breathtaking, gripping, terrifying (just choose your own superlative and apply it) story. The intriguing police procedural element is layered with aspects of national and international importance and has such resonance in today’s world that the real life potential of this fiction is unnervingly plausible. I cannot stop contemplating what happens, so that the effect of reading Body of Lies is profound. It’s impossible to review Body of Lies without spoilers, but I cannot stress strongly enough how good it is or how fitting the title is.
With Kat’s partner, Lock, being AI, the effects and implications of how we create, use and control AI all feature throughout the book and I adore Jo Callaghan’s skill in presenting both positive and negative aspects without steering the reader to one particular viewpoint. Body of Lies is a book that is intelligently written and not only entertains flawlessly, but that makes the reader think long after the final page is read.
However, amongst a superb plot are themes of humanity that thrum with sensitive understanding, and affect the reader emotionally too. Kat’s PTSD following events in Human Remains, her ongoing grief at losing her husband, her desire to protect her adult son Cam as well as give him freedom and autonomy, her professionalism and strength as a DCS and her vulnerability, loneliness and compassion, all combine to make her a sublime character. Add in politics, national and international security, cyber attacks, trust, betrayal, zealousness and professional relationships, and Body of Lies transcends mere entertainment.
I realise this review is slightly vague as I really don’t want to spoil the story for others, but let me just say that Body of Lies is magnificent. It appeals to a wide range of emotions, and engages the reader completely. Indeed, I defy any reader not to shed a tear in reading it. Jo Callaghan is not only a sublime author, but her writing illustrates her as a superbly human individual who cares about her characters. Body of Lies is completely wonderful and not to be missed.
I am at a complete loss to know how to review Body of Lies. I thought it was utterly fabulous. There are so many aspects to Jo Callaghan’s insightful writing that each book rewards multiple reads and Body of Lies is no exception.
Obviously plot is of supreme importance and in Body of Lies there is a breathtaking, gripping, terrifying (just choose your own superlative and apply it) story. The intriguing police procedural element is layered with aspects of national and international importance and has such resonance in today’s world that the real life potential of this fiction is unnervingly plausible. I cannot stop contemplating what happens, so that the effect of reading Body of Lies is profound. It’s impossible to review Body of Lies without spoilers, but I cannot stress strongly enough how good it is or how fitting the title is.
With Kat’s partner, Lock, being AI, the effects and implications of how we create, use and control AI all feature throughout the book and I adore Jo Callaghan’s skill in presenting both positive and negative aspects without steering the reader to one particular viewpoint. Body of Lies is a book that is intelligently written and not only entertains flawlessly, but that makes the reader think long after the final page is read.
However, amongst a superb plot are themes of humanity that thrum with sensitive understanding, and affect the reader emotionally too. Kat’s PTSD following events in Human Remains, her ongoing grief at losing her husband, her desire to protect her adult son Cam as well as give him freedom and autonomy, her professionalism and strength as a DCS and her vulnerability, loneliness and compassion, all combine to make her a sublime character. Add in politics, national and international security, cyber attacks, trust, betrayal, zealousness and professional relationships, and Body of Lies transcends mere entertainment.
I realise this review is slightly vague as I really don’t want to spoil the story for others, but let me just say that Body of Lies is magnificent. It appeals to a wide range of emotions, and engages the reader completely. Indeed, I defy any reader not to shed a tear in reading it. Jo Callaghan is not only a sublime author, but her writing illustrates her as a superbly human individual who cares about her characters. Body of Lies is completely wonderful and not to be missed.
April 14, 2026
DCS Kat Frank returns to work at the Future Policing Unit after a tragic loss, only to find herself thrust into a new high-profile case. On the night of Halloween a local MP is found murdered, with a taunting message written in binary code that seems to target Kat specifically: Catch me if you can. The victim’s anti-AI sentiments suggest a political motive & as Kat investigates with her partner AIDE Lock – the world’s first AI detective – she finds herself once again battling her own prejudices about the technological future he represents. But when a cyberattack takes out the National Grid, Kat & Lock have to race against the clock to track down the hacker before thousands die. Tangled in a web of suspicion & deception, Kat must choose who and what to believe when the truth seems to defy both instinct and logic.
So firstly, let me admit that I’ve been lucky enough to have a proof of this title since The end of last year, I have picked it up many times to read but because I didn’t want it to all be over I’ve ended up delaying reading until now!
I knew this fourth, and final, book in the series would be everything I wanted it to be & more, & I wasn’t wrong. After the dramatic events at the end of the last book (no spoilers!) I was desperate to know what direction this book took, and wow, what a journey.
From the outset we catch up with Kat who is thrown into a new case that is evident will cause questions to be raised. Jo’s powerful, engaging & captivating writing style continues to evoke every emotion possible from the reader - honestly this whole series has just been an emotional rollercoaster!
I don’t want to give anything away in regards to how the series ends but I think that Jo has achieved this perfectly. I for one am devastated that the series has come to an end, however it is a fitting conclusion that will definitely satisfy the readers who have come to love these characters.
One thing is for certain, I cannot wait to see what Jo has in store for us next, I will be first in the queue to find out! Well done Jo and thank you for allowing us to share the world of Kat & Lock with you.
(And if you’ve not read this series - rectify that now, you’ve got a month to read the first three books!🙂)
So firstly, let me admit that I’ve been lucky enough to have a proof of this title since The end of last year, I have picked it up many times to read but because I didn’t want it to all be over I’ve ended up delaying reading until now!
I knew this fourth, and final, book in the series would be everything I wanted it to be & more, & I wasn’t wrong. After the dramatic events at the end of the last book (no spoilers!) I was desperate to know what direction this book took, and wow, what a journey.
From the outset we catch up with Kat who is thrown into a new case that is evident will cause questions to be raised. Jo’s powerful, engaging & captivating writing style continues to evoke every emotion possible from the reader - honestly this whole series has just been an emotional rollercoaster!
I don’t want to give anything away in regards to how the series ends but I think that Jo has achieved this perfectly. I for one am devastated that the series has come to an end, however it is a fitting conclusion that will definitely satisfy the readers who have come to love these characters.
One thing is for certain, I cannot wait to see what Jo has in store for us next, I will be first in the queue to find out! Well done Jo and thank you for allowing us to share the world of Kat & Lock with you.
(And if you’ve not read this series - rectify that now, you’ve got a month to read the first three books!🙂)
Review of advance copy received from Publisher
Thanks to Simon and Schuster for the gifted proof of this title in return for an honest review.
This is an epic conclusion to the series - which includes In the Blink of An Eye, Leave No Trace, and Human Remains - and whilst it is epic, the fact that it's the last one is just not good news, because this has been just one of the greatest series I've read. Whilst Jo has done a wonderful job in rounding everything up, I don't like the idea that there won't be another to look forward to.
Like I said with the previous books, Jo has an amazing capacity for writing about grief, which I imagine comes from her own bereavement. As someone who has lost a lot of people, I find it really difficult to explain just how I feel but she's taken the words straight from my heart and it's just beautiful.
I think it's a very timely book. Obviously the whole series is about AI, but this one looks into the safety of it, the job losses, and that is becoming a genuine fear, particularly in the creative industries, and so whilst it was a thoroughly enjoyable book, it is also thought-provoking.
Also this idea of an MP being killed. No matter what their policies, no-one deserves to be murdered, but sadly this is not solely found in fiction.
I found Lock was quite irritating in this one, for the most part (he does redeem himself as the book goes on). That's not a negative point, but rather a compliment to Jo's writing. We have seen this "man" go through four books and he has grown and learnt and is as close to human as AI can be, and with that comes new emotions, new reactions, new intelligence, and it's frightening.
Whilst the other books did focus on AI, obviously, it was more in relation to the crimes. Whereas this one looks at it on a more national and global scale, and looks at how much we rely on AI, robots, electricity, machines; we focus on how it can help and ignore how it can harm.
This is about more than "just" a murder; it has so many layers to it, feels more personal and more targeted.
It is rounded off nicely, everything tied up, but I still can't believe it's finished. I've spend the last few years excited for the next instalment, and now that's it. But it'll be interesting to see what avenue Jo goes down now.
This is an epic conclusion to the series - which includes In the Blink of An Eye, Leave No Trace, and Human Remains - and whilst it is epic, the fact that it's the last one is just not good news, because this has been just one of the greatest series I've read. Whilst Jo has done a wonderful job in rounding everything up, I don't like the idea that there won't be another to look forward to.
Like I said with the previous books, Jo has an amazing capacity for writing about grief, which I imagine comes from her own bereavement. As someone who has lost a lot of people, I find it really difficult to explain just how I feel but she's taken the words straight from my heart and it's just beautiful.
I think it's a very timely book. Obviously the whole series is about AI, but this one looks into the safety of it, the job losses, and that is becoming a genuine fear, particularly in the creative industries, and so whilst it was a thoroughly enjoyable book, it is also thought-provoking.
Also this idea of an MP being killed. No matter what their policies, no-one deserves to be murdered, but sadly this is not solely found in fiction.
I found Lock was quite irritating in this one, for the most part (he does redeem himself as the book goes on). That's not a negative point, but rather a compliment to Jo's writing. We have seen this "man" go through four books and he has grown and learnt and is as close to human as AI can be, and with that comes new emotions, new reactions, new intelligence, and it's frightening.
Whilst the other books did focus on AI, obviously, it was more in relation to the crimes. Whereas this one looks at it on a more national and global scale, and looks at how much we rely on AI, robots, electricity, machines; we focus on how it can help and ignore how it can harm.
This is about more than "just" a murder; it has so many layers to it, feels more personal and more targeted.
It is rounded off nicely, everything tied up, but I still can't believe it's finished. I've spend the last few years excited for the next instalment, and now that's it. But it'll be interesting to see what avenue Jo goes down now.
April 8, 2026
I feel truly honored to have an ARC of this book, one of the most anticipated reads for me in 2026 and an autobuy author that I've stuck with since 2023. In my opinion, to fully appreciate this series, you MUST read them from the start.
Kat and Lock have become an obsession of mine. They are a detective duo that have made a true imprint on the crime fiction world.
This show-stopper book has left me with a hangover that's tainted with some bittersweet sadness due to their story ending here. Callaghan has meticulously manufactured a superior ending, which this series rightfully deserved. I unequivocally adored this book.
This story runs parallel to the heart-pounding finale of 'Human Remains' and emotionally propels you into the depths of its clutches.
DCS Kat Frank and her AI assistant AIDE Lock are put to work when the body of the local MP is discovered. The body's disposal is disturbing, and when a secret message is revealed, what none of us realise is that this is the beginning of the end.
This series is poignant and timely due to the current AI fascinations that the world has. It's a highly controversial topic and one that I often see debates about. Callaghan's astute knowledge is objective and impartial, allowing the reader to make their own judgment on AIDE Lock and what he represents for the future. Nonetheless, this story will make you question whether we fully understand the dangers AI may pose to our world.
Callaghan emphatically explores trauma, loss, and grief within this series. I feel this book authentically represented the true turmoil of human emotions. It demonstrates how driven we can be because of our feelings and then identifies the analytical difference between us and AI.
I actually come away feeling like I've learned a lot, like the reliance we have on electricity.
This is a brutally dark, fast-paced, cyber-crime heavy novel. It's packed with subjects for your mind to continuously unpick.
Its unpredictable nature did not prepare me for what was to come.
Pure ingenious brilliance.
Kat and Lock have become an obsession of mine. They are a detective duo that have made a true imprint on the crime fiction world.
This show-stopper book has left me with a hangover that's tainted with some bittersweet sadness due to their story ending here. Callaghan has meticulously manufactured a superior ending, which this series rightfully deserved. I unequivocally adored this book.
This story runs parallel to the heart-pounding finale of 'Human Remains' and emotionally propels you into the depths of its clutches.
DCS Kat Frank and her AI assistant AIDE Lock are put to work when the body of the local MP is discovered. The body's disposal is disturbing, and when a secret message is revealed, what none of us realise is that this is the beginning of the end.
This series is poignant and timely due to the current AI fascinations that the world has. It's a highly controversial topic and one that I often see debates about. Callaghan's astute knowledge is objective and impartial, allowing the reader to make their own judgment on AIDE Lock and what he represents for the future. Nonetheless, this story will make you question whether we fully understand the dangers AI may pose to our world.
Callaghan emphatically explores trauma, loss, and grief within this series. I feel this book authentically represented the true turmoil of human emotions. It demonstrates how driven we can be because of our feelings and then identifies the analytical difference between us and AI.
I actually come away feeling like I've learned a lot, like the reliance we have on electricity.
This is a brutally dark, fast-paced, cyber-crime heavy novel. It's packed with subjects for your mind to continuously unpick.
Its unpredictable nature did not prepare me for what was to come.
Pure ingenious brilliance.
Review of advance copy received from Publisher
I have been eager to read the fourth book in the series, albeit with some trepidation. You know to a certain extent from the previous book where the story is going and I don’t mind admitting that I didn’t want to face it.
I love Kat and Lock. Against her better judgement, Kat has some what reluctantly been working alongside Lock. There is no denying what a massive help he is to the team and whilst technology can be a wonderful thing, it also can be scary. Lock may be a computer but I know I am not the only one who has grown extremely fond of him over the course of this series. They have definitely bonded and there has been some humour as well as emotions along the way.
Their most recent case shows the level of damage that can be done by a cyber attack and how reliant we are on so many things we take for granted. It is actually quite horrifying! It is a race against time to find out who is behind the attack before anymore people lose their lives. It’s a complex case which shocked me to the core with its revelations. There is no denying that this book is going to hit fans of the series hard, I know it did me.
Body of Lies was such an emotional roller coaster of a ride. I don’t think I have ever sobbed whilst reading a crime thriller before but I have now. These books highlight the good and bad of human nature as well as technology. Whilst I believe the outcome was the right one, it doesn’t mean it is the one that I wanted. Kat and Lock have been a breath of fresh air when it comes to crime thrillers and each book has been outstanding in their own rights. I can’t recommend them highly enough. They give readers so much food for thought. A book and series that will truly blow your mind!
I love Kat and Lock. Against her better judgement, Kat has some what reluctantly been working alongside Lock. There is no denying what a massive help he is to the team and whilst technology can be a wonderful thing, it also can be scary. Lock may be a computer but I know I am not the only one who has grown extremely fond of him over the course of this series. They have definitely bonded and there has been some humour as well as emotions along the way.
Their most recent case shows the level of damage that can be done by a cyber attack and how reliant we are on so many things we take for granted. It is actually quite horrifying! It is a race against time to find out who is behind the attack before anymore people lose their lives. It’s a complex case which shocked me to the core with its revelations. There is no denying that this book is going to hit fans of the series hard, I know it did me.
Body of Lies was such an emotional roller coaster of a ride. I don’t think I have ever sobbed whilst reading a crime thriller before but I have now. These books highlight the good and bad of human nature as well as technology. Whilst I believe the outcome was the right one, it doesn’t mean it is the one that I wanted. Kat and Lock have been a breath of fresh air when it comes to crime thrillers and each book has been outstanding in their own rights. I can’t recommend them highly enough. They give readers so much food for thought. A book and series that will truly blow your mind!
Review of advance copy
I am probably a bit of a traditionalist when it comes to detective thrillers. My typical read would be to absorb myself in the worlds of human detectives tracking down the baddies. So I was a little unsure if the Kat (DCI) and Lock (AIDE) series would engage my attention given it introduced the application of a concept which my little brain finds difficult to comprehend, that of Artificial Intelligence in policing.
However, after being totally engrossed in book one of the series, thanks to an author who sure knows how to make a scientific concept, AI, seem simple, credible and actually could add tangible value, I was very keen to read more in the series. This, together with a wonderful use of the written word to bring to life full and rounded fictional personalities and a captivating plot.
Body of Lies is book 4 in the series and whilst I did feel I would have benefited from reading books 2 and 3, it did not spoil my pleasure of the story.
Whilst Body of Lies falls into the realms of fiction, there was much to this book that left me feeling that it was not far short of being a fascinating insight into the reality of the application of artificial intelligence in the real world. Yet at the heart of the book, was still an engaging crime thriller, characters who you believed in and a plot that still saw those baddies being caught. Loved it.
However, after being totally engrossed in book one of the series, thanks to an author who sure knows how to make a scientific concept, AI, seem simple, credible and actually could add tangible value, I was very keen to read more in the series. This, together with a wonderful use of the written word to bring to life full and rounded fictional personalities and a captivating plot.
Body of Lies is book 4 in the series and whilst I did feel I would have benefited from reading books 2 and 3, it did not spoil my pleasure of the story.
Whilst Body of Lies falls into the realms of fiction, there was much to this book that left me feeling that it was not far short of being a fascinating insight into the reality of the application of artificial intelligence in the real world. Yet at the heart of the book, was still an engaging crime thriller, characters who you believed in and a plot that still saw those baddies being caught. Loved it.
Review of advance copy received from NetGalley
The final book in the DCS Kat Frank and AIDE Lock series and I recommend reading the series in order as each follows directly on from the previous book. Following the events of the last book Kat is back at work, still grieving, and is due to attend a Parliamentary committee session to discuss rolling out more AIDE’s to police forces and whether the earlier events affect the proposals. As always this is so well written and a completely addictive read, I didn’t want to put it down.
Briefly, in Coleshill, Warwickshire there is a sudden electricity cut and in the middle of this Kat is called out when an anti-AI MP is found dead and exhibited in the town’s medieval pillory. When the cause of her death is discovered the case goes right to the top involving the Prime Minister and their entire Cabinet as the nation is held to ransom.
In a clever twisty drama Kat and AIDE are faced with not just finding a murderer but ensuring the safety of those closest to Kat. The issue of AI, not just relating to crime but on a more worldwide scale is considered from both sides of the argument. It is really well researched and adds volumes to the story without answering the question. Is the idea of AI good or bad? Shocks and twists all along with a dramatic conclusion. Another brilliant book, I’m just sad it’s the last one.
Briefly, in Coleshill, Warwickshire there is a sudden electricity cut and in the middle of this Kat is called out when an anti-AI MP is found dead and exhibited in the town’s medieval pillory. When the cause of her death is discovered the case goes right to the top involving the Prime Minister and their entire Cabinet as the nation is held to ransom.
In a clever twisty drama Kat and AIDE are faced with not just finding a murderer but ensuring the safety of those closest to Kat. The issue of AI, not just relating to crime but on a more worldwide scale is considered from both sides of the argument. It is really well researched and adds volumes to the story without answering the question. Is the idea of AI good or bad? Shocks and twists all along with a dramatic conclusion. Another brilliant book, I’m just sad it’s the last one.
Review of advance copy received from Publisher
Book 4 of the Kat and Lock series, and the final book 😢 I love this series and characters, Lock maybe a hologram but how can you not love him. I will miss reading about this team of crime fighters and look forward to what Jo has in store for us next.
After the devastating events of the last book, Kat has been living in a hotel and off work. The start of Body of Lies sees her return home to get her life back on track again. She soon finds herself investigating murder of a local MP, whose body is found after a blackout. The MP happens to be an anti AI campaigner so this case is personal. Plenty of people weren’t fans of the MP so the list of potential suspects is long.
This is such a clever and unique series, not your average police procedural. The addition of an AI detective who doesn’t understand sarcasm and takes everything at face value is an interesting twist. The banter between Kat and Lock is hilarious. Their relationship has grown with each book and it quite emotional. A crime story with heart and will absolutely make you think about the use of AI in today’s society.
I highly recommend this series, read in order of course. I guarantee you will fall in love with these characters.
After the devastating events of the last book, Kat has been living in a hotel and off work. The start of Body of Lies sees her return home to get her life back on track again. She soon finds herself investigating murder of a local MP, whose body is found after a blackout. The MP happens to be an anti AI campaigner so this case is personal. Plenty of people weren’t fans of the MP so the list of potential suspects is long.
This is such a clever and unique series, not your average police procedural. The addition of an AI detective who doesn’t understand sarcasm and takes everything at face value is an interesting twist. The banter between Kat and Lock is hilarious. Their relationship has grown with each book and it quite emotional. A crime story with heart and will absolutely make you think about the use of AI in today’s society.
I highly recommend this series, read in order of course. I guarantee you will fall in love with these characters.
Review of advance copy received from Publisher
Body of Lies is the perfect finale to what has been a truly exceptional series. It’s fair to say that the DCS Kat Frank and AIDE Lock novels are my all time favourite series and with book 3 finishing on a huge cliff-hanger, I couldn’t wait to find out how it was all going to end!
I’m not going to tell you anything about the plot - I went into it knowing nothing and I think that’s the best way. At this point if you haven’t read books 1 to 3 then go back and read them first, this is a series you definitely want to read in order to get the most out of it.
If I was to try and sum this book up I’d say it was poignant, funny, thrilling, exciting, terrifying, shocking but ultimately so moving and human. It gave me everything I wanted and so much more. The twists and turns were exquisitely plotted with references back to earlier books that just reinforced for me how much of a genius Jo is!
I did not see the ending coming, yet it made perfect sense once all had been revealed - always the sign of a truly great book in my opinion. And as is customary in this series there’s one final moment to leave you staring at the wall open-mouthed!
Jo really struck gold with the inclusion of AI in a police procedural when she came up with this series but it’s her knowledge, skill and sheer brilliance that have made it such a special set of books. They really are an example of how fiction novels can broaden your mind, your understanding, and your empathy - if only the humans will listen.
I’m not going to tell you anything about the plot - I went into it knowing nothing and I think that’s the best way. At this point if you haven’t read books 1 to 3 then go back and read them first, this is a series you definitely want to read in order to get the most out of it.
If I was to try and sum this book up I’d say it was poignant, funny, thrilling, exciting, terrifying, shocking but ultimately so moving and human. It gave me everything I wanted and so much more. The twists and turns were exquisitely plotted with references back to earlier books that just reinforced for me how much of a genius Jo is!
I did not see the ending coming, yet it made perfect sense once all had been revealed - always the sign of a truly great book in my opinion. And as is customary in this series there’s one final moment to leave you staring at the wall open-mouthed!
Jo really struck gold with the inclusion of AI in a police procedural when she came up with this series but it’s her knowledge, skill and sheer brilliance that have made it such a special set of books. They really are an example of how fiction novels can broaden your mind, your understanding, and your empathy - if only the humans will listen.
Review of advance copy received from Author
Thank you so much for my gifted proof from Simon and Shuster. Farewell Kat and Lock in their final instalment! This series has been a firm favourite of mine. DCS Kat Frank has returned to the Future Policing Unit in Warwickshire after a terrible incident six months ago. I wanted to take my time reading this so I read a few chapters every day to make it last. After a body of MP is found murdered with a taunting message written in binary code that seems to target Kat and Lock "Catch me if you can". Can Kat and Lock solve this crime? Will they find the culprit? How does this tie in with Angela's views on AI and their proposed advances? The team must race to find answers amidst the chaos of a cyberattack that affects the National Grid! It was dark, disturbing, engrossing, fast paced, full of twists and turns, humorous in places, nail biting and above all tense and terrifying and unputdownable! The subject matter does make you think on how this AI technology can affect human lives and their work. I will miss you!
Review of advance copy received from Author
Body of Lies - the dramatic conclusion to the Kat and Lock series by Jo Callaghan.
If you haven’t pre-ordered this, take this as your sign! And if you haven’t read the series yet? What are you waiting for?
This series is cemented as one of my all time favourites. Not only is the writing fantastic, but the concept is original and the cast of characters are diverse with depth and growth that develops with each book.
The Future Policing Department continue to investigate crimes- Kat leading the operation with her experience, gut and instincts; and Lock, the AI detective entity who contributes facts, data and research. But this time, it’s bigger than either of them could have anticipated.
These characters are going to stay with me for a long time. I can’t believe it’s over… But that’s the good thing about books; they can be rediscovered over and over again.
A huge thank you to the incredible Jo Callaghan for joining us at Telford Book Club recently and for gifting me a proof copy of Body of Lies 🖤 I truly cannot wait to see what’s next📚
If you haven’t pre-ordered this, take this as your sign! And if you haven’t read the series yet? What are you waiting for?
This series is cemented as one of my all time favourites. Not only is the writing fantastic, but the concept is original and the cast of characters are diverse with depth and growth that develops with each book.
The Future Policing Department continue to investigate crimes- Kat leading the operation with her experience, gut and instincts; and Lock, the AI detective entity who contributes facts, data and research. But this time, it’s bigger than either of them could have anticipated.
These characters are going to stay with me for a long time. I can’t believe it’s over… But that’s the good thing about books; they can be rediscovered over and over again.
A huge thank you to the incredible Jo Callaghan for joining us at Telford Book Club recently and for gifting me a proof copy of Body of Lies 🖤 I truly cannot wait to see what’s next📚
Review of advance copy received from Publisher
*Book Review*
I’m not gonna lie, I don’t even know where to start with this review 🤯🤯🤯!!
This has to be one of the most anticipated books of 2026 (well it is for me anyways) and I can’t believe i was so lucky to receive an arc for @jocallaghankat latest and sadly final instalment of the Kat and Lock series 😭
I have been hooked on this duo since I discovered them in book one way back in 2024 🫶🏻 they are just fabulous in every single way!!
Callaghan has definitely pulled all the stops out with this one, the way she created the tension in the story all the way to the end is just phenomenal!! Let’s not talk too much about that ending as it has left me with a hole in my heart that I’m still trying to fix and I finished this book over a week ago! Yes that’s how long it has taken me to get my head back in check to write this review!
To fully appreciate this series you have to start at the very beginning as the story flows right from the first word in “in the blink of an eye” to the final full stop of “body of lies”.
For me this book is very “on trend” right now with the AI side of the storyline as everyone at the moment seems to hyped on it and how it all works! You can see quite clearly the knowlege and research that has gone into AI and its well, quite possible dangers! By the end I felt well and truly educated on something I didn’t know much about!! It’s rather scary if it falls into the wrong hands!
You are taken on one hell of a rollercoaster of emotions. You are continuously given nuggets to unpick. Just when you think you’ve got this you are thrown the opposite direction!
Edge of the seat, dark, fast paced…..
Pure imaginative talent!!
10/10 Callaghan!!!
I read this with the bestie @_what_katie_read_ make sure you check out her review as well!
I’m not gonna lie, I don’t even know where to start with this review 🤯🤯🤯!!
This has to be one of the most anticipated books of 2026 (well it is for me anyways) and I can’t believe i was so lucky to receive an arc for @jocallaghankat latest and sadly final instalment of the Kat and Lock series 😭
I have been hooked on this duo since I discovered them in book one way back in 2024 🫶🏻 they are just fabulous in every single way!!
Callaghan has definitely pulled all the stops out with this one, the way she created the tension in the story all the way to the end is just phenomenal!! Let’s not talk too much about that ending as it has left me with a hole in my heart that I’m still trying to fix and I finished this book over a week ago! Yes that’s how long it has taken me to get my head back in check to write this review!
To fully appreciate this series you have to start at the very beginning as the story flows right from the first word in “in the blink of an eye” to the final full stop of “body of lies”.
For me this book is very “on trend” right now with the AI side of the storyline as everyone at the moment seems to hyped on it and how it all works! You can see quite clearly the knowlege and research that has gone into AI and its well, quite possible dangers! By the end I felt well and truly educated on something I didn’t know much about!! It’s rather scary if it falls into the wrong hands!
You are taken on one hell of a rollercoaster of emotions. You are continuously given nuggets to unpick. Just when you think you’ve got this you are thrown the opposite direction!
Edge of the seat, dark, fast paced…..
Pure imaginative talent!!
10/10 Callaghan!!!
I read this with the bestie @_what_katie_read_ make sure you check out her review as well!
April 3, 2026
I have read all of the books in this series and really enjoyed them and this one certainly didn’t disappoint. It was great to be back with DCS Kat Frank and her team, including AIDE Lock.
After the horrible events of Kat being held captive and the explosion she has been away from her home and her work for six months. She was dreading being back in her house because of what happened there and couldn’t stop thinking about it.
It was good to have Kat and Lock back working together and doing what they did best together, which was solve crimes.
The body of a local MP- Angela Long- was found staged in some stocks in the town centre during a town wide power cut. The team worked hard to establish who has murdered her and what their motive was.
A visit to Westminster for Kat and AIDE Lock rapidly turned into a horrible situation that saw the whole of the UK under threat. Could they work out who was behind it all within a stressful and very time critical situation?
A fab read and I’m sad to see the series end. I would definitely recommend this book and this series.
After the horrible events of Kat being held captive and the explosion she has been away from her home and her work for six months. She was dreading being back in her house because of what happened there and couldn’t stop thinking about it.
It was good to have Kat and Lock back working together and doing what they did best together, which was solve crimes.
The body of a local MP- Angela Long- was found staged in some stocks in the town centre during a town wide power cut. The team worked hard to establish who has murdered her and what their motive was.
A visit to Westminster for Kat and AIDE Lock rapidly turned into a horrible situation that saw the whole of the UK under threat. Could they work out who was behind it all within a stressful and very time critical situation?
A fab read and I’m sad to see the series end. I would definitely recommend this book and this series.
This entire review has been hidden because of spoilers.
Review of advance copy received from Netgalley
I was a bit late to the party with this series, I dont know why, I think the cover of Blink of an Eye and knowing it was about AI put me off,but I absolutely fell in love with AIDE Lock in book#1 and have continued to do so, despite hating myself! DCS Kat Frank is so relatable and likeable as a character and she has really developed throughout the series.
Knowing this was the series finale I wondered how it would end, and I shan't give any spoilers, but if you're a fan it is wonderful and awful all at the same time. I found this book different from the others in that it was a lot less about Kat and the crime and more about Lock and the technological side of using AI, which I found less interesting and I found it got a bit bogged down by government business 2/3 of the way through. However, it really picked up the 'Can AI have agency?' debate towards the end, and it really was a fantastic poignant ending.
Knowing this was the series finale I wondered how it would end, and I shan't give any spoilers, but if you're a fan it is wonderful and awful all at the same time. I found this book different from the others in that it was a lot less about Kat and the crime and more about Lock and the technological side of using AI, which I found less interesting and I found it got a bit bogged down by government business 2/3 of the way through. However, it really picked up the 'Can AI have agency?' debate towards the end, and it really was a fantastic poignant ending.
Review of advance copy
Firstly thank you to The Book Club reviewer group on facebook for this advance copy.
There are no spoilers in this review.
These books all follow on from each other so I would definitely recommend that you read the earlier books before moving on to this one.
This is a the final novel of the series and it does not disappoint. There is the murder to solve but there is also the ongoing relationship between Kat, Lock and the rest of the team. The characters are well rounded and have developed on from the first book, making you care about them all.
The book follows on from the events of the last book and the team’s loss. Lock is as logical as ever giving rise to some gentle humorous moments. Kat is cautious and Mcleish as grumpy as usual.
The book makes you think about the limits of AI, the limits of humans and the limits of the human/AI connection.
An excellent and fitting conclusion to the series.
There are no spoilers in this review.
These books all follow on from each other so I would definitely recommend that you read the earlier books before moving on to this one.
This is a the final novel of the series and it does not disappoint. There is the murder to solve but there is also the ongoing relationship between Kat, Lock and the rest of the team. The characters are well rounded and have developed on from the first book, making you care about them all.
The book follows on from the events of the last book and the team’s loss. Lock is as logical as ever giving rise to some gentle humorous moments. Kat is cautious and Mcleish as grumpy as usual.
The book makes you think about the limits of AI, the limits of humans and the limits of the human/AI connection.
An excellent and fitting conclusion to the series.
January 26, 2026
Synopsis——Human suspicion. AI manipulation.
Who can you trust when truth has no meaning?
DCS Kat Frank returns to work at the Future Policing Unit after a tragic loss, only to find herself thrust into a new high-profile case. On the night of Halloween a local MP is found murdered, with a taunting message written in binary code that seems to target Kat specifically: Catch me if you can.
The victim’s anti-AI sentiments suggest a political motive, and as Kat investigates with her partner AIDE Lock – the world’s first AI detective – she finds herself once again battling her own prejudices about the technological future he represents. But when a cyberattack takes out the National Grid, Kat and Lock have to race against the clock to track down the hacker before thousands die.
#mythoughts no spoilers! totally brilliant to be back with Kat and Lock. If you loved the other books in this series you will love this one you might shed a tear just saying ….
Who can you trust when truth has no meaning?
DCS Kat Frank returns to work at the Future Policing Unit after a tragic loss, only to find herself thrust into a new high-profile case. On the night of Halloween a local MP is found murdered, with a taunting message written in binary code that seems to target Kat specifically: Catch me if you can.
The victim’s anti-AI sentiments suggest a political motive, and as Kat investigates with her partner AIDE Lock – the world’s first AI detective – she finds herself once again battling her own prejudices about the technological future he represents. But when a cyberattack takes out the National Grid, Kat and Lock have to race against the clock to track down the hacker before thousands die.
#mythoughts no spoilers! totally brilliant to be back with Kat and Lock. If you loved the other books in this series you will love this one you might shed a tear just saying ….
Review of advance copy received from Publisher
Body of Lies is book four of The Kat and Lock series and what a finale to a brilliant series.
DCS Kat Frank is head of the future Policing unit with AIDE Lock in Warwickshire. After being off work for the last six months after an accident and the death of her partner she return to work. Her first case is the murder of a local MP which was found dead after a blackout. With a message in binary code saying catch me if you can. The local MP Angela was against AI o I was wondering if that was one of the causes of her death.
I am grateful for the copy of Body of lies. This is a brilliant action-packed thriller and excellent finale book in a great series. To be honest, I am gutted this is the last one. I thoroughly enjoyed this series with its unique storyline which came I came to love the character of Locke. 5 stars from me.
DCS Kat Frank is head of the future Policing unit with AIDE Lock in Warwickshire. After being off work for the last six months after an accident and the death of her partner she return to work. Her first case is the murder of a local MP which was found dead after a blackout. With a message in binary code saying catch me if you can. The local MP Angela was against AI o I was wondering if that was one of the causes of her death.
I am grateful for the copy of Body of lies. This is a brilliant action-packed thriller and excellent finale book in a great series. To be honest, I am gutted this is the last one. I thoroughly enjoyed this series with its unique storyline which came I came to love the character of Locke. 5 stars from me.
April 26, 2026
I am absolutely devastated this series has finished but wow what an ending!
Body of lies is the fourth in the series and picks up after the events in book 3. It can be read as a standalone but works best after reading the first three.
A powercut and murder of a local MP draw Kat, Lock and the FPU team into the world of politics, where AI is a highly controversial topic and leads to a cyberattack which causes the national grid to go down and power to be lost to the whole of the UK.
The plot is brilliant and the characters well developed. The clever writing will make you forget Lock is AI at times and become emotionally attached to him in the same way Kat does.
Absolutely loved this book and the whole series, I am looking forward to see what Jo Callaghan writes next.
Thanks to THE Book Club Reviewer Group and Simon and Schuster UK for the advanced copy.
Body of lies is the fourth in the series and picks up after the events in book 3. It can be read as a standalone but works best after reading the first three.
A powercut and murder of a local MP draw Kat, Lock and the FPU team into the world of politics, where AI is a highly controversial topic and leads to a cyberattack which causes the national grid to go down and power to be lost to the whole of the UK.
The plot is brilliant and the characters well developed. The clever writing will make you forget Lock is AI at times and become emotionally attached to him in the same way Kat does.
Absolutely loved this book and the whole series, I am looking forward to see what Jo Callaghan writes next.
Thanks to THE Book Club Reviewer Group and Simon and Schuster UK for the advanced copy.
January 6, 2026
I had an early Christmas present last year - I feel very privileged to have received this advanced readers copy of AIDE Lock’s last book of the series!!!
Kat and Lock’s partnership grows stronger as the world goes into turmoil. A local MP is found murdered, and while the Future Policing Unit try to wrap their heads around the cause of death, a cyberattack takes out the National Grid. It’s a race against time to restore electricity before further catastrophes strike.
As always, Jo has delivered - this was outstanding, keeping me guessing throughout. It is great end to the series, although I am gutted it’s over.
The book is due for publication in May 2026. You DO NOT want to miss it!
Kat and Lock’s partnership grows stronger as the world goes into turmoil. A local MP is found murdered, and while the Future Policing Unit try to wrap their heads around the cause of death, a cyberattack takes out the National Grid. It’s a race against time to restore electricity before further catastrophes strike.
As always, Jo has delivered - this was outstanding, keeping me guessing throughout. It is great end to the series, although I am gutted it’s over.
The book is due for publication in May 2026. You DO NOT want to miss it!
Review of advance copy received from Publisher
I’m not crying YOU’RE crying, oh good this book, I’m not sure if I want to tell the author that I’m not having any of that ending and the book needs a rewrite or to congratulate her on one of the best books/series ever!
This really really can’t be the end, like many others I have been invested in Kat and Lock since the beginning and didn’t want the series to end.
What an ending we got, this is definitely a book to binge, I had to know what would happen next, the different settings were perfect for getting across the seriousness of the situation and how frightening it was. I loved how Cam played his part in it all and I was completely shocked by the reveal and never saw it coming.
My favourite part had to be Lock and his sarcasm! I felt like a proud parent!
This really really can’t be the end, like many others I have been invested in Kat and Lock since the beginning and didn’t want the series to end.
What an ending we got, this is definitely a book to binge, I had to know what would happen next, the different settings were perfect for getting across the seriousness of the situation and how frightening it was. I loved how Cam played his part in it all and I was completely shocked by the reveal and never saw it coming.
My favourite part had to be Lock and his sarcasm! I felt like a proud parent!
Review of advance copy received from Author
This is the fourth book in this great series featuring DCS Kat Frank & Aide Lock a AI detective. It has been a brilliant series and sorry that it has come to an end. I really don't know how I can do justice to what I have just read it's an emotional rollercoaster of a read. Kat has just returned to work at the future policing unit after a tragic loss. She is immediately thrown into a high profile case involving the death of a local MP but there is a message that looks like its aimed directly at her. She doesn't know who or what to trust anymore. A brilliant end to an brilliant series highly recommend.
Review of advance copy received from Author
I have really enjoyed this series about Lock an AI hologram detective, which is such a great idea. I have been impressed by the way the author has managed to deliver a pacy thriller without shying away from discussing the pros and cons of AI and the oversight that needs to be in place to ensure it's use is safe.
In this story, after the death of a local MP, the country is held to ransom by someone who has shut down the national grid. The author juggles the multiple elements well and her characters are interesting and have good emotional depth.
Highly recommended (the whole series).
In this story, after the death of a local MP, the country is held to ransom by someone who has shut down the national grid. The author juggles the multiple elements well and her characters are interesting and have good emotional depth.
Highly recommended (the whole series).
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