The Treehouse is a very dark and intense novel and I was completely drawn into and mesmerised by the first half. Teenage brothers Kieran and Robert commit a horrific act on holiday in Cornwall with their family. Twenty years later the past revisits them when a drama is made which seems to echo these events from the past.
The author brilliantly portrays the relationship between the brothers. The novel is told from each brother’s perspective with some contributions from their mother June. This really builds up the tension and intensity between them and left me holding my breath at times.
For me the novel was less successful when it moved back to the past and the events of 2004.
Many thanks to NetGalley and the publisher for the opportunity to read and review this digital ARC.

A good and twisty thriller with domestic and psychological elements. well done
Highly recommended.
Many thanks to the publisher for this ARC, all opinions are mine

The Treehouse by B.P. Walter starts off strong. There are dark secrets, ominous family dynamics, a treehouse that practically screams “don’t climb in unless you enjoy lifelong emotional damage.” I was all in. I lit a candle, made tea, and prepared to be psychologically wrecked.

And then... the book kind of just sat there, brooding in a corner.

To be fair, Walter knows how to set a creepy tone. The atmosphere is tense, the characters have that delightfully twisted “everyone needs therapy and maybe an exorcism” energy, and the premise drips with potential. But somewhere between the past and present timelines, the suspense went out for milk and never came back.

Revelations are teased with all the urgency of a DMV line. You’ll spend chapters waiting for something explosive, only to find out, “Oh, THAT’S the big secret? Neat.” Plot twists land with a thud, and some characters are so emotionally constipated you’ll want to shake them and say, "Use your words!"

That said, it’s not a bad read. It’s just a moody slow-burn thriller that sometimes forgets to actually thrill. Think of it as psychological suspense on decaf—mildly stimulating, but unlikely to keep you up at night.

Recommended if you enjoy family dysfunction with a side of ominous metaphors and don’t mind a plot that occasionally wanders off to check its phone.

Trigger warning: I was unable to read this book. I do not know what happened to the girl in the treehouse but the prologue led me to believe it was a "sicko" event and she died. Possibly at the hands of 2 boys. I am sure that there is an explanation in the book for what really happened, but I am unable to continue. Thank you to NetGalley and One More Chapter for the opportunity to read this book but I will need to pass. This is my honest review, in my own words.

The Treehouse was a little dark for my taste.
Two brothers whilst on holiday in Cornwall committed an act in the treehouse in the garden neither of have spoken about again until now. They have to speak about it as somehow there is a tv programme on called “the treehouse” and shows exactly what they did in there. How can this have happened if neither have spoken to anyone and who is this person.
This was a book I had high hopes for but wasn’t totally for my tastes. The book took a long time to get where it was going and the ending although felt rushed did deliver everything it should and had a good twist. The characters were all very different, some very strong and others very weak so that worked well. I didn’t like that in my mind it is more horror than thriller and definitely needs trigger warnings. I didn’t guess the twist but it was surprising and well timed when it came.
I would like to thank NetGalley and HarperCollins UK and One More Chapter for this ARC I received in exchange for an honest review.

This was a great read! There were so many twists and turns and kept me on the edge of my seat! I couldn’t put it down!

A recent television series causes the lives of brothers Kieran and Robert Palmer to implode as it reveals secrets from something that happened over twenty years ago, an event which they had thought buried forever. As teenagers they spent a fateful summer in Cornwall with their parents and during this time they became involved in something which would have a lasting effect on all of their lives going forward. The significance of the treehouse, such a brooding character, plays out its own role in the story and as we become part of the narrative we watch in horror as Kieran and Robert act out their fantasies with terrible consequences.

Taut with tension, and alive with deceit, a tangled web of secrets and lies start to emerge and with such a set of unstable narrators you are never quite sure where the truth ends and the lies begin. I raced through the story in just few hours, compelled to read further just to see how this complex story would play out and I wasn’t disappointed. There are twists and turns aplenty, with the last third of the story revealing far more about this dysfunctional family than I could have ever thought possible.

Well written, with a clever sense of time and place, and with totally unlikeable characters who worm their way into your mind, The Treehouse is a complicated story of murder, tragedy and deadly family secrets.

Walter‘s books are always an excellent read! And the latest book was no different The Treehouse was an excellent story with superb twists and turns from the beginning that made it a great page turner. The storyline and characters were excellent. Kept me up and turning pages way past my bedtime.
The suspense and plot was very well thought out with lots of twists and turns that ensure you won’t put the book down.
This was another great thriller.

I enjoyed reading The Treehouse and the way the plot expanded more as you read on. The split narration between characters and years was really well done and never felt confused or knotted up on itself.
The ending however didn't work 100% for me, it was maybe one twist too many.
This said though, I did very much enjoy The Treehouse and would recommend to anyone looking for a thriller/mystery with a bit of a difference

Robert and Kieran are two brothers, not only bound by blood, but also by a dark secret from 20 years ago. As an adult, Robert is living a careful life and no longer close to his brother. When he sees a trailer for an upcoming TV show called The Treehouse, his carefully curated world comes to a halt. Somehow, someone knows what happened 20 years ago. But who could possibly know and why is it coming to the surface now?

This novel was much darker than what I was expecting! Immersive and unsettling, I would definitely say this is more like a psychological horror / thriller then a normal family drama like the blurb hints at. Told from multiple POVs and timelines, The Treehouse expertly blends psychological suspense with atmospheric tension and unresolved trauma. There are definitely some dark topics that are discussed including animal cruelty on and off page, drug use, trauma, sacrificial killing, and the occult, so please be aware before reading and protect your peace! Overall, if you like dark psychological suspense novels full of unresolved generational trauma and twists that catch you off guard, give The Treehouse a shot!

Thank you to NetGalley, B P Walter, and One More Chapter for this ARC! Publication date is July 3rd 2025.

Sharp and sinister, The Tree House is B.P. Walter at his most devious. What begins as a detached viewing of a murder-themed pseudo-documentary soon turns into a reckoning for two brothers, Keiran and Robert — because the fictional story being aired to millions? It’s uncomfortably similar to something they were part of. Something buried. Something real.

Walter cleverly uses the true-crime docuseries format to frame this chilling tale, blurring the lines between scripted drama and lived horror. As the layers peel back, we see just how far Keiran was willing to go in his ambition — with Robert always a step behind, a reluctant witness to what ambition and pathology can breed.

The brilliance of the book lies not in shock value (though there’s plenty of that), but in the slow realization that nothing, and no one, is as innocent as they seem. Every memory is suspect. Every family story has its cracks.

If you love thrillers that twist your expectations and leave you questioning who the real victims are, The Tree House delivers in spades.

#HarperCollinsUK #OneMoreChapter #theTreehouse #BPWalter

This book centres around two brothers Robert & Kieran and something they did over 21 years ago. Will their secret come out?


This book outlines how things change within the brother’s relationship and their family when they get older and something threatens to reveal a dark secret they have been keeping.


This story has plenty of intrigue, mystery with dark elements around animal sacrifice. It kept me intrigued throughout the book and I would like to thank netgalley for the ARC of this book.

I am getting more into reading thrillers and this was much darker than I am used to in the genre. I really enjoy the multiple POVs and flashbacks. It definitely kept me on the edge of my seat. I really enjoyed this book a lot and would recommend it to my thriller reading friends or friends who love true crime. I feel like I will need to give quite a few warnings to people before recommend it though.

Brothers, secrets, a dark past, a treehouse, and a horrible tragedy! In their youth, brothers Robert and Kieran made some horrific choices and actions. Both hope that that time in their past is behind them but there is a new show coming out titled "The Treehouse" and to say that it freaked Robert out. The thought that someone out there knows what they did all those years ago, has him on edge and panicking.

What is their deep dark secret? What happened all those years ago and what happens if their secret is revealed? Those questions are what drives the plot which tells the story in past and present timelines.

This book was heavy on atmosphere and tension. I also enjoyed the twists and turns along the way. Plus, more than one shocking reveal had me thinking "holy crap!" as I did not see-that-coming-at-all. The author does a good job at showing the underlying dread and anxiety that Robert was feeling. As the book moved along, it becomes more and more evident that this family puts the dysfunction in dysfunctional family.

Overall, an enjoyable, dark and twisted tale!

The Treehouse by B.P. Walter is set to be published by One More Chapter on the 3rd July 2025.

4.5 stars

Brothers Robert and Kieran have seemingly perfect lives. Yes, they may be single, but Kieran is a lottery winner who spends his time on benders when he should be helping their mum care for their very ill father. Robert has an S1 flat, a nice, caring roommate called Albie and a job he loves. That is, until the start of a new ITV drama, when everything starts falling apart.

How can The Treehouse, the new must-see show everyone is talking about, depict in so much detail an event which happened to the brothers twenty years ago? To make matters worse, it's an event both brothers would rather forget. Just who knows what they did?

I had been meaning to read Walter’s The Garden Party for a while and finally did in June this year. Suffice it to say that I loved it, I love any author who brings queer themes to genres that don't always have them, and so when I saw Walter had another book coming out, I jumped at the chance to read and review it. It was also nice to see a little nod to that book in the mention of the Moncrieffs as the people who gifted Robert and Kieran’s mother a vase.

There's a strong mystery here that I really enjoyed, which delves into a wide variety of topics I wasn't expecting it to cover. Radicalisation, the power of the internet, and themes which seem to be prevalent in much of Walter's work like brotherhood, generational trauma, family dynamics.

My main issues with the story are with things like how conciliatory it is towards Piers Morgan (using words like ‘expert’ to describe someone who is effectively just a bigot with a megaphone is an odd choice), and the scenes of drugged-up heterosexual debauchery in the early Kieran-focussed chapters, which do get a bit tiresome. I was also disappointed by the lack of queer themes in this one, after they were so important to The Garden Party (I couldn't help but hope something might happen between Robert and Albie, if I'm completely honest). Despite this I did find The Treehouse even more intriguing than its predecessor in lots of ways. It's also a blooming good, enjoyable read generally.

This is my second of Walter's books and it definitely won't be the last, he's really great at getting you to care about morally ambiguous characters for whom the word complex doesn't even begin to cover it. And each book seems to leave you in a completely unexpected different place from where you start them at, it's insane in many different ways, and brilliant.

If you want a twisty, gripping thriller which will defy your expectations, The Treehouse is a brilliant choice (as is The Garden Party).

This one was not for me. I persevered to about the halfway mark but couldn’t keep reading. I’ve enjoyed previous titles by BP Walter but The Treehouse was just too dark and too out there for my liking.
Thank You to NetGalley and HarperCollins UK, One More Chapter for the Exclusive Accesss to this ARC but unfortunately it wasn’t for me.

The Tree House is a psychological thriller with a difference. I can’t say I was fully prepared for the content and feel that it would be perhaps too dark for some readers. But I appreciate that it is a topic that I haven’t read before.

I felt the book took a long time getting to the main point, and the ending felt very rushed, but did have a surprising twist at the end.

Thank you to NetGalley, the author and Harper Collins Uk, One More Chapter for access to this eARC in exchange for an honest review.

From reading the blurp I was really excited to read this book. I got to 50% and had to DNF.
This book should have trigger warnings

B.P. Walter’s The Treehouse is a tightly wound psychological thriller that masterfully explores the shadowy terrain of guilt, family dysfunction, and long-buried secrets.

It’s a compelling, character-driven novel that unspools with increasing tension, anchored by a central mystery that refuses to stay buried.

The story revolves around Robert and Kieran Drinkwater, two brothers bound by blood and something far darker - a terrible act committed during a family holiday in Cornwall more than twenty years ago.

Now adults, Robert is a successful charity worker with a carefully maintained life. But that life begins to unravel when a TV show trailer titled The Treehouse flashes across his screen. Someone knows what happened all those years ago. The question is: who and why now?

Told predominantly from the alternating perspectives of Robert and Kieran, with piercing, often unsettling interjections from their sharp-tongued mother June, the novel’s strength lies in its rich, layered characterisation.

Robert is steeped in guilt and anxiety, a man teetering on the edge, always needing reassurance and seemingly incapable of outrunning the past.

Kieran, by contrast, is more self-assured but not necessarily more innocent. Their dynamic is complex and ever-shifting, oscillating between codependence, rivalry, and desperation.

June, the matriarch is snobbish, strong-willed, and deeply flawed.

Her voice brings an acerbic sharpness that cuts through the narrative with chilling clarity. This isn’t a typical family, and Walter takes pains to explore the intricate and often toxic bonds that bind them.

The titular treehouse looms both literally and metaphorically. It’s the site of the original sin and becomes a symbol of suspended trauma — an eerie, half-forgotten place that casts long shadows over the present.

Walter uses it to great effect, both as a setting and as a metaphor for the instability and danger lurking beneath the family’s fragile façade.

What starts as a simmering drama gradually becomes a full-throttle thriller.

Walter skillfully builds suspense, layering twist upon twist, each one more unsettling than the last.

The dual timelines are deftly handled, keeping the reader guessing as past and present begin to merge in disturbing ways.

The transformation of the brothers’ dark secret into a televised drama is a particularly clever device.

It raises provocative questions about voyeurism, memory, and public vs private trauma. How do you live a normal life when your worst moment is being reinterpreted — and possibly exposed — to the world?

Ultimately, The Treehouse is not just a story of a crime, but a study in the corrosive power of secrets and the lengths people will go to keep them buried. Walter deftly explores how guilt, shame, and unresolved trauma can shape and warp a life.

Haunting, immersive, and deeply unsettling, The Treehouse is another standout novel from B.P. Walter.

This is psychological suspense at its finest — dark, emotionally resonant, and impossible to look away from.

Thanks to NetGalley and HarperCollins One More Chapter for the ARC in exchange for an honest review.

I went into this not sure what to expect and ended up really enjoying this read. The story centers on Kieran and Robert, two brothers. In their youth, they worshipped each other until something happens on a family holiday involving a treehouse. As adults, the brothers, no longer close, are each living what appears to be their best lives, or maybe not. A TV series comes out depicting events that seem to mirror the events from that long-ago holiday. The story is told in dual timelines and as we learn more and more, the creepier the story gets. Dark family secrets, lies and lots of unlikeable characters take you on a slow burning ride until a twist ending that I never saw coming! I think this would have been a perfect Fall release just due the spooky atmosphere, but either way, still a good book. I am going to try more from this author from sure.

Thank you to #NetGalley, B P Walter and HarperCollins UK, One More Chapter | One More Chapter for this ARC. All opinions are my own.

I will post my review to Amazon, Barnes and Noble, Instagram and other retail and social media sites upon publication day of July 3, 2025.