How far would you go to protect your child? Simone is about to find out.

Simone’s childhood was anything but easy. With parents lost to addiction, she spent years in foster care before carving out a future on her own. Through grit and determination, she built a successful business and found her anchor in Damian. Together they raised their daughter Lucy who became the heart of Simone’s world. Maybe because of her past, Simone tends to hover, fiercely protective. So a camping trip in Texas felt like a rare chance for quality time before Lucy heads off to university.

But their getaway turns into a nightmare. On the first morning, Simone wakes to find Lucy gone. A chilling text arrives, followed by a video: Do what I say. Don’t call the police if you want to see her again.

Her instincts take over. She calls Damian, but with him 5,000 miles away, and wary of Simone’s plan, she knows she’s on her own. The kidnapper doesn’t want money. Instead, Simone must cross the border into Mexico to collect a package, then return it in exchange for Lucy. The task is dangerous and illegal, yet for Simone, there’s no question. She’ll risk everything.

As a mother of daughters, this story hit home for me. It’s a tense, high-stakes thriller, but also a moving look at the bond between a mother and child. I loved the way Simone’s memories of Lucy, and her relationship with Damian, are woven through the action. Short, punchy chapters and occasional shifts in POV keep the tension sharp, and the twists don’t let up until the end.

What I loved
- The nuanced relationship between Simone and Lucy
- The moral conflict versus a mother’s fierce instinct
- Simone and Damian’s layered partnership
- A clever final twist that ties everything together

What didn’t quite land for me
- The pacing slows a little mid-book as character backstory takes center stage
- Apart from a hairbrush, they seemed to have all the necessary clothes, toiletries and food that they needed throughout their time on the run.
- Their time in the wilderness felt a little unrealistic, knowing how many mosquitos and wild animals there would have been plus the physical skills needed to walk such a distance.

Thanks to NetGalley for an advance copy in return for my honest review.

Gillian McAllister has a way of writing thrillers that are both utterly gripping and deeply human, and Caller Unknown is no exception. The premise hooked me right away—a mother waking up to find her daughter missing, a phone left behind, and a kidnapper demanding the unthinkable. From the opening chapters, the tension is relentless, and I found myself holding my breath more than once as Simone raced against the clock in the Texas desert.

What I loved most is that this wasn’t just a high-octane thriller—it was also a thoughtful exploration of motherhood, morality, and how far someone will go to protect the person they love most. Simone is a character who feels real and flawed, making impossible choices that force the reader to ask: “What would I do?” The shifting dynamics between her, Lucy, and her husband added layers of emotional complexity that elevated the story beyond a standard kidnap narrative.

The pacing is fast and addictive, though I’ll admit there were a couple of moments where the plot stretched believability just a bit. Still, McAllister’s skill at balancing heart-pounding suspense with raw, emotional stakes more than made up for it.

Overall, Caller Unknown is tense, thought-provoking, and impossible to put down—a perfect mix of adrenaline and heart. Fans of Wrong Place Wrong Time will not be disappointed.

Not for me unfortunately. I found it very slow moving and hard to keep interested. I’m sure this is someone’s cup of tea, just not mine!

Gillian’s books are either hit or miss for me and I’m always nervous because I don’t know which it will fall into but this one was very good! I did enjoy it a lot! Thank you NetGalley and publisher for early arc

What would you do to get your daughter back from a kidnapper? I know I would go to the ends of the earth to get her back! Simone would too.

This is an amazing story of a mother’s love. Her intuition. Trusting her gut. Never underestimate a mama bear.

The premise of this book was so strong: a mother and daughter go camping in a cabin. The mother wakes up after their first night to find that her daughter is gone, and in her place, a phone. The kidnapper uses the phone to instruct the mother about the crazy lengths she needs to go to in order to get her daughter back.

The synopsis gave me The Chain vibes and I was so excited for it! The start is a bit slow as the mother (Simone) makes her way to visit her daughter (Lucy), all the while reminiscing about how much she loves Lucy and how much she misses her. The kidnapping takes place quickly, and the quest begins.

Minor spoiler for the first 1/4 of the book: Simone's mission is to smuggle drugs across the border. That's it. It turns what I thought would be more a mystery-focused thriller into a 200 page-long chase sequence as the drug smuggle inevitably goes a bit wrong. This part of the book kind of lost me as it wasn't the most interesting to just watch Simone run around the desert.

There was a small plot twist toward the end of the book, and while I like the way that it concluded the story, I think that it left a lot to be desired. There seemed to be several plot holes at the end, and I was hoping for more after all of the build-up.

The mother-daughter relationship was by far the best part of the book. At first, I thought Simone was a bit emotionally dependent on her daughter, but as their characters and relationship was developed, I came to appreciate their bond.

Overall, this was a fine thriller, a bit chase/running away-heavy for my liking. I really liked Famous Last Words by McAllister, and this didn't quite beat that in my rankings.

Thank you to NetGalley + William Morrow for the ARC

Not the vacation gone wrong in Texas of all places! As a native Texan this plot intrigued me and I love all things Gillian McAllister. This is a cat and mouse style thriller but also very much about mother and daughter dynamics. I found their relationship painful at times and it definitely impacted my enjoyment of this story. Thanks to Netgalley and the publisher for my ARC!

This book just didn’t work for me. I kept waiting for twists or surprises to keep me hooked, but there was only one reveal at the very end and it wasn’t much of a shock. The pacing felt slow, and I had a hard time staying interested.

I also struggled with the believability of the plot. So much of it depended on the idea that the police wouldn’t have believed the characters, but that explanation never really rang true. Instead of feeling suspenseful, it pulled me out of the story.

I usually enjoy McAllister’s writing, but this one missed the mark for me.

Caller unknown opens up with a mother's worst nightmare — while on vacation in the desert with her daughter she wakes to find her daughter's bed empty.
As her panic mounts, she searches the cabin for any signs her daughter left on her own volition to make a quick stop somewhere. Then she gets a call from an unknown caller with the news that changes everything - we have your daughter. What ensues is the age old question of how far a mother would go to save her child.
This story did not unfold the way I expected it to, and at times felt a little far fetched (but everything is bigger in Texas so l guess this checks out). Even so, Gillian McAllister has this way of writing novels that keep you invested and on the edge of your seat while also pulling at the fabric of what makes us human. While this did have slower portions with the way it was broken up, l still could not put it down. There was also at least one twist that I did not see coming, which is unusual for me as l've gotten very good at predicting them these days.
This was a very satisfying novel with an equally satisfying ending, I almost didn't want it to be over.
Every novel I have read by her has stuck out in my brain and caller unknown is no exception. I can't wait for everyone to read this book!!

https://www.goodreads.com/review/show/7912001311

Okay so… this one was kinda a mixed bag for me. The setup had me instantly hooked, like nightmare fuel in the best possible way. A missing daughter, a ransom call, and a mom who will literally do anything? Total page-turner vibes at first. But then the middle slowed down a lot and I found myself low-key frustrated with some of the choices the characters kept making. It’s one of those thrillers where you keep wanting to yell at the page, you know?

That said, I did enjoy the mother-daughter dynamic, even if it was a little over the top at times, and the Texas desert setting gave the whole thing this tense, gritty energy. I just wish the pacing had stayed as sharp as the beginning because it could have been such a knockout.

Still, if you’re into messy moral dilemmas and high-stakes family drama, it’s definitely worth picking up.

Thank you to NetGalley for the ARC in exchange for my honest opinion.

Thank you to NetGalley and the publisher for allowing me to read this book. This was my first Gillian McAllister book. I really enjoyed this. I loved all the twists and turns and didn’t expect the ending! Make sure to out this one in your TBR!

This had a bit of a slower start for me, but it really picked up with a lot of twists that changed the direction of the plot and where I thought it was going. The whole book was almost like a thriller meets human nature case study on the psychology of mother-daughter bonds in different environments. Loved this latest addition to the Gillian McAllister works!

What a twisty story! The things a mother will do to help her daughter! It was very captivating storyline.

Caller Unknown by Gillian McAllister
ARC Review releases May 2026
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I loved this book, it had me on the edge of my seat the entire time. To what length would you go to rescue your daughter?!

Simone and Lucy are on a girls trip in Texas. When Simone wakes up the next morning Lucy is nowhere to be found. There is a burner phone, the unknown caller says don’t call the police and makes unthinkable illegal demands. Simone must race against time to rescue Lucy. This book explores the extreme lengths a mother will go for her child and setting in motion a chain of life changing events.

Absolutely gripping!! I couldn’t put it down. The twists kept me hooked the entire way, and the concept felt fresh and original. McAllister does suspense so well, and this one proves it.

Thanks for the review copy. This is quite the page turner. And holy plot twist, Batman. I would never have guessed it. People are going to love this one.

Simone lives in the UK and is visiting her daughter, Lucy, in TX where Lucy has been attending camp. Simone can't wait to start their own camping trip together till she awakens one morning to find Lucy has been kidnapped and a burner phone has been left. Everything from there spirals.

The book started strong with the first half immediately pulling you in and the mystery was well-constructed early on. However, as the plot progressed, the pacing began to drag on with random flashback in the past that didn't quite make sense and the constant mention of her restaurant back home. The second half felt uneven and at times drawn out. It has a promising start, but didn’t quite deliver on its initial suspense.

I for some reason though the daughter, Lucy, was somehow possibly involved in her own kidnapping she was bratty throughout the book and an unlikeable character. The mom, Simone, would do anything for her daughter but obsession with her daughter is a bit much and some of the decisions she made were reckless and making her character unlikeable as well.

The twist at the ending I didn't see coming and seemed a little far fetched.

Thank you to NetGalley, the author and publisher for this ARC in return for my review

I have liked Gillian McAllister's past books but this one fell flat for me

When Simone goes to Texas to visit her daughter, Lucy, she is looking forward to spending some quality time together. What she isn't expecting, is to wake up to a quiet cabin, Lucy nowhere in sight.

When Simone is sent a ransom, in exchange for Lucy's safe return, she goes into Maternal Overdrive.

The kidnapper makes it very clear that she is not to go to the police, but aren't the police the ones who can truly help?! What lengths will Simone go to in order to save her daughter? How is she going to find her on her own? Will she have to give in to the kidnapper's requests?

Give it a read to find out!

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I usually LOVE McAllister's books. This one, was a bit iffy for me. The book is broken into multiple "parts" to go over different storylines throughout
The earlier part of the storyline came to a close much quicker than I expected. I thought it would have dragged out a bit longer. Then toward the end, it felt like it was a bit rushed through and kind of thrown together. I would have loved some more detail (but don't want to give any spoilers).
There was also a twist that really threw me off. Not in a way that impressed or bamboozled me, but it genuinely confused me for a bit and I had to go back and re-read some things a few times, until I was able to figure out what was going on. I'm not sure if that's just me, or if anyone else had an issue with it.

I definitely still think you should give this book a read when you have a chance, if her other stories have been ones that you've enjoyed! It just wasn't AS good for me as some of her previous works.

In Caller Unknown a mother goes to great lengths to rescue her kidnapped daughter. Told from the mom’s and kidnapper’s POVs, you follow mainly Simone as she tracks down her daughter. This book starts off slow and didn’t really pick up pace wise. I really wanted to get into the story but the events seemed just kind of average. The writing is strong and ultimately kept me reading. I didn’t love Simone as a main character, especially her relationship with her husband. I think there could’ve been more action, but this was more focused on the mother/daughter relationship. (3/5)

**This ARC was provided by the publisher via Netgalley in exchange for an honest review.**

Gillian McAllister is back and once again, I was not let down. Caller Unknown was twisty, emotional and hard to put down. It had me hooked right away and although some moments felt a little far fetched, it was overall a good read. Thank you NetGalley and William Morrow for this advanced readers copy in exchange for my honest review.