Today I’m sharing my review of Body of Lies by Jo Callaghan. This was one of my most anticipated reads of 2026, having devoured and loved the Kat and Lock series. Everything comes to a head in this epic conclusion, but would it hold up to my expectations?
Thank you to Simon & Schuster for gifting me a proof in exchange for an honest review.
This review originally appeared on The Nerd Daily.
DCS Kat Frank is back at the Future Policing Unit after a devastating loss – and straight into her most disturbing case yet. On Halloween night, a local MP is found murdered. Beside the body is a taunting message in binary code, aimed directly at Kat:
Catch me if you can.
The victim was a vocal opponent of AI. The motive looks political. But as Kat investigates with her partner, AIDE Lock – the world’s first AI detective – the case spirals into something far more dangerous. Then a cyberattack takes down the National Grid.
With the country in chaos and lives on the line, Kat and Lock must track a killer who is always one step ahead. But in a world of deepfakes, deception and digital ghosts, instinct is no longer enough. Kat must decide whether to trust the one thing she still fears most: her AI partner.
Because this time, Lock may not just be solving the case. He may be changing what it means to be human. Can Kat stop a killer before the lights go out for good?
CW: murder, death, violence, gore, grief, injury
My Thoughts:
Body of Lies was one of my most-anticipated thrillers of the year. Luckily it does not disappoint with an unforgettable conclusion to one of the best crime series I have read.
Jo Callaghan struck gold with the Kat and Lock series which has this wonderfully cognisant concept of the first AI police aid and the technology-hating detective forced to work with him. It is an ingenious evolution of a familiar trope and then it is combined with a heartfelt, nuanced and hard-hitting exploration of grief. This is explored beautifully. The series arc between these two characters keeps it as a theme throughout and Kat’s storyline is realised with a tenderness and sensitivity that lands that much more impactfully. On top of this, you have wonderful characterisation (the supporting cast will steal a spot in your brain and heart); grisly, gnarly plots that go there with the darkness and twists that will leave you reeling. With this in mind, it will not come as a surprise that I have devoured the Kat and Lock series over the past year and was delighted to get stuck into the finale. This was especially after that explosive conclusion of Human Remains.
Body of Lies starts with a bang. That opening chapter is something I do not think I will have out of my brain for quite some time. It is uncannily reminiscent of the news headlines and I have always enjoyed the way that Callaghan uses these books to explore political themes, particularly around government bodies and the role of the police in the modern era. She is not afraid to talk about tough topics and that continues here. This particular plot takes Kat and Lock into new territory as the ramifications of this murder unravel a much wider plot.
As a reader, Kat and Lock have always been the beating heart of this series. Kat is a character that I will forever treasure. She is this no-nonsense, brilliant detective that is struggling with her own grief and the guilt she feels over the consequences of previous books. Her character arc over this series is exceptional and so raw and tender. You just want to shelter her from the world but know that she is needed to be protecting those she loves and cares for. As a detective, she is gifted and trusts her instincts in a way that Lock cannot understand. With Lock, Callaghan has delivered a masterclass in characterisation with, transforming this AI tool into a character that you come to care about and root for. He feels so real and a lot of this is to do with just how he has transformed over the course of these books. That character arc is fraught and readers will spend much of this book debating over what they can trust and wondering if anyone is lying to them. After the conclusion of the previous book, we are in uncharted territory and Callaghan ensures that these are murky waters indeed. The two of them together are dynamite with dialogue that is razor-sharp and often contains a kernel of humour in the face of the bleakness they are facing.
This is such a brilliantly put-together book. It is tight and tense with stakes that are higher than ever. The events of previous books still hang over all of the characters and massively influence how they navigate the world. That personal darkness is mirrored by the very tangible darkness they are all facing, an unthinkable evil that threatens everything they know and love. This is matched with a breathtaking pace that keeps you glued to the pages until the early hours. There are twists and turns along the way that genuinely caught me by surprise. Among these pages are betrayal, secrets and lies that are all coming to the light at last. The shining beacon of this series has always been the humanity of these characters and now that very love you have is being turned on you as a weapon. Everything builds to an inspired ending that felt perfect to me. No spoilers here but I think readers will be satisfied, though you cannot stop concentrating until the very final sentence.
Body of Lies is a tightly plotted and explosive conclusion to a phenomenal series that deserves legendary status. If you haven’t started the Kat and Lock series, do yourself a favour and go pick them up immediately.
A Short Book Lover 