The Unwelcome Guest: A Thriller

by Cori Nevruz

A dream vacation becomes a living nightmare in The Unwelcome Guest.

When four brothers and their wives reunite for a long-awaited getaway, the private island they’ve chosen seems like the perfect sanctuary. The mansion they’ve rented is a haven of a sprawling library, a state-of-the-art gym, and breathtaking views from every window. It’s a paradise designed to bring the family closer, a place to unwind and rekindle bonds.

But beneath the island’s tranquil façade, something sinister stirs. It starts subtly—an uneasy feeling, items vanishing, and sounds resonating from deep within the mansion’s walls. What initially seems harmless escalates into something much darker. Accidents grow too precise, too deliberate. The sensation of being watched is impossible to shake.

As fear takes hold, the family discovers they are completely cut off: no cell service, no internet, and the boat that brought them won’t return for days.

The Unwelcome Guest bides his time, hiding in the walls, waiting for the perfect moment to strike while the family’s dream vacation turns into a deadly nightmare they can’t escape.

Genres: Thriller, Ebooks

279 pages, Kindle Edition

Published June 3, 2025

About the author

Cori Nevruz is a suspense and thriller author known for her gripping narratives and psychological depth. She has penned five novels: Murder Manor (Coming February, 2026), A psychological thriller with a whisper of the paranormal—book your stay at the manor, but beware: not every guest checks out; The Unwelcome Guest, An island escape, a mansion of dreams... and a nightmare hiding within; Making a Killing (previously published as Noxious), a chilling tale of a lethal assassin targeting retired pensioners;  Left Without Answers, which follows a mother teetering on the edge of madness in her quest for justice; and Dirty Laundry, a fast-paced thriller that delves into the unraveling mind of a mom pushed to her limits.
Cori resides in Wilmington, NC, where she balances her writing career with family life alongside her husband and three sons. When she's not crafting thrilling stories, she enjoys reading and following her favorite sports.

Reviews

[Tonya · Rating 3 out of 5]

The Unwelcome Guest is a beautifully written character-driven thriller with creepy vibes. Tensions run high as one near-death experience after another plagues the vacationing family expecting fun and relaxation instead of death lurking behind every hidden door. The final shocking twist was the perfect ending to this story of jealousy, betrayal, and deception. Thank you BookSirens for my copy.

[Cori Nevruz · Rating 5 out of 5]

It's my book. I'm kind of biased :)
However, I wrote it based on the fact I wanted to read a suspenseful, psychological thriller that takes place on a private island in a luxurious mansion with all sorts of secrets... so I wrote it. I hope you love it too!

[Elle · Rating 4 out of 5]

I was really hoping that I would enjoy this and thankfully I did! The cover, title, and description sounded exactly like a book that I would like so I'm glad that it delivered.

Four brothers and their wives go to a private island (always a great idea, right?) and everything seems perfect. Soon, a suspicion that things aren't quite right start to creep in. Personal belongings going missing, the feeling of being watched, and dark "pranks."

I thought this book was well-written and did a fantastic job of keeping me engaged in the story. While being a bit of a shorter book, it didn't feel underdeveloped to me and the pacing was pretty steady throughout the story. Besides the initial plot setup in the beginning, everything progressed pretty quickly. I loved reading the perspective of the "unwelcome guest" while also bouncing between the normal perspective of the other guests. This was suspenseful and did a good job of casting suspicion on the characters.

My only complaint, if you can call it that, is that the reveal started to seem a bit obvious to me. I don't always mind this though as long as I'm still enjoying the story along the way, and that was the case here. The ending also felt a bit quick to me but sometimes that's to be expected with shorter books.

Overall, I really enjoyed this and my complaints are pretty minor. Thank you to BookSirens for the ARC. All opinions are my own.

TW: Confinement, Death, Domestic abuse, Misogyny, Physical abuse, Violence, Stalking, Murder, Gaslighting, Injury/Injury detail

StoryGraph Review
Fable Review

[jillian · Rating 3 out of 5]

The cover and description pulled me into this one. It was a short enough book to be an easy read in a sitting or two.

What I liked:
-Premise
-Writing style easy to follow
-Vacation descriptions: yummy food scenes, water scenes
-This book will give you the chaos you want
-Easy read, finished in a sitting

What prevented a 5 star rating:
-For me, this book had a lot of build up and I was hoping to be more invested towards the end
-I think was wanting more than creepy subtle hints and more drama and action
-I think for me as a reader I either want humor thrown in and ridiculousness or constant action in my thrillers with just enough character development to be invested, I felt like this book was right in the middle

I received an advance review copy for free, and I am leaving this review voluntarily.

[Katy The Sleepy Reader · Rating 5 out of 5]

Any time Cori has a new book out its a no brainer to pick it up. Everything that I have read of hers is fantastic and this was no exception.

The book centers around a family vacation coordinated by a woman named Crystal and her husband Jonah. Joining them on this weeklong getaway on a secluded island are Jonahs's brothers, Thomas and his wife Ilma, Sean and his wife April and the youngest and single brother Will. Crystal and her husband Jonah are hosting the soiree and Crystal is loving every minute of it. This island getaway has been on her bucket list for years and years. She finally has the chance to do it and she makes it as lavish as possible.

The mansion that is located on this serene island is nothing short of amazing. It has everything you could possibly want and need and even seems tailored to each of the people coming on this vacation. Crystal loves the lavishness of the island and mansion. Sean and April love the state-of-the-art gym as they own a gym and live every minute in the fitness world. Thomas and Ilma are teachers, and Ilma has a love of libraries so the tremendous library within the mansion is just the place for the introverted, quiet woman. The mansion also has an amazing and well stocked kitchen for Will, a trained chef.

There is another more malevolent entity on the premises: an unwelcome guest. The vacationers start to feel things happening. Sounds behind walls, a boiling hot tub, things going missing, shadows and the feelings of being watched. When things start to take a darker turn, fingers are pointed, and more than feelings will be hurt before it's all over.

The island itself it but off from everything. No internet, no cell phones, no way off until the week is over. The unwelcome guest is hiding, weaving his way inside the walls, and just waiting for the perfect time to strike and enact his plan. Can the guests of the island figure out what's going before the unwelcome guest is able to complete his plans?

I cannot tell you enough how much I loved this book. The story is amazing, there's just no other way to describe it. I love the character and world building. But the twist at the end was what really made this a great story. I did not see it coming. If you love a great psychological thriller then this is the book for you. I received this book from the author for an honest review.

[Amanni Evans · Rating 4 out of 5]

The Unwelcome Guest started off at a slower pace, but once it picked up, I was completely hooked. Cori Nevruz masterfully builds suspense, layering in tension and uncertainty until I found myself flying through the pages. Every twist felt intentional, and the story unfolded in such a satisfying way. By the time I reached the ending, everything clicked into place perfectly, it was one of those rare conclusions that made the whole journey worth it. If you enjoy domestic thrillers that sneak up on you and then won’t let go, this one’s worth the read.

I received an advance review copy for free, and I am leaving this review voluntarily.

[Beverly · Rating 3 out of 5]

I was very ambivalent about the book. I didn't like it (especially the women because they were unlikable each in their own way) ,

it seemed trite and repetitive after a point.

The pranks and shenanigans were getting tiresome, and I was relatively sure I knew who the unwelcome guest was, and I was pretty much on their side-sorry. They had a point, but maybe went about it the wrong way. I was over the little tricks and wanted it to end. Not my cuppa. I voluntarily read a free copy of this book provided by book sirens and am giving an honest review.

[Sue Johnston · Rating 5 out of 5]

This was a real page turner. It kept me reading late into the night, needing to know what would happen next. Fast paced from the beginning with amazing descriptive writing that transports you to the world the author's created for you. Believable characters and dynamics play out to a brilliant conclusion.

I received an advance review copy for free, and I am leaving this review voluntarily.

[Christie · Rating 5 out of 5]

This was my first book by this author, and it will not be my last, as I already have her book Making a Killing. I LOVED this book and could not put it down. It kept me guessing throughout the entire book. The characters were great, a mix between likeable and not likeable, all at the same time.

[Diane Elizabeth Taylor · Rating 5 out of 5]

This atmospheric thriller plunges a family gathering on a remote, luxurious island into chilling disarray.
As inexplicable events escalate and the wives feel increasingly targeted by a malevolent presence, a palpable sense of foreboding grips the reader.
The author masterfully portrays distinct personalities and their growing unease amidst the stunning yet isolating setting.
With skillful prose and expertly crafted tension, the narrative builds towards a brilliant twist that recontextualizes everything. A truly excellent and unsettling read.
My thanks to BookSirens and the author for the opportunity to read this book as an advance copy. My review is my own.

[Nikki Losin · Rating 4 out of 5]

The unwelcome guest captured a family vacation bathed in luxury and intrigue with eerie thriller vibes mixed in.

[Elisa · Rating 5 out of 5]

This is a very entertaining, suspenseful whodunit in the tradition of And Then There Were None. Four brothers and their three wives (the youngest is still unmarried) travel to a private island where they will be totally alone in a luxurious mansion. From the beginning, readers know that they are sharing their retreat with the titular Unwelcome Guest, who is watching them. Little inconveniences turn into more serious mishaps, but no one is too concerned. It’s the wives who keep saying that something is very wrong but, as with most husbands everywhere, the men think they are overreacting. I loved the house with all its amazing features. The themed rooms seemed a little over the top, but we don’t read these books for verisimilitude. I was also a bit confused as to things the Unwelcome Guest did and certain twists that seemed a bit implausible but, again, I wasn’t too bothered. And that is because I liked all the characters, even the most flawed ones. They’re all well-known types: the sophisticated rich couple, the sporty ones, the unlikely joker/bookworm combo and the kid who’s grownup, but they seemed real and I was worried about them. I wasn’t a fan of the eldest couple, but I truly liked the rest of the cast. A quick, fun, escapist read that will make you happy not to be able to afford a private island.
I received an advance review copy for free, and I am leaving this review voluntarily. Thank you, BookSirens.

[Georgette · Rating 3 out of 5]

this was an ARC for me. a big old mansion with hidden tunnels and passages on a private island. what 's not to love. this could have been a really good book. the story was great. Except that about the 30% mark the proofreader and the copy editor both apparently quit. some of the authors extensive descriptions got a bit wordy but he definitely got the point across. i guess the author though he was trying to impress by taking a normal word and adding to it to make it into not-word. i was not impressed. quite the contrary, it made him look uneducated. that coupled with his ever lengthening descriptions and wordy tangents off into never-never land that had nothing to do with the story line almost made me stop before the 50% mark. by about the 75% mark the author must've realized that he needed to wrap things up because the chapters went from long and flowing to short and abrupt. then the abrupt exposure of the identity of the "unwelcome guest"was just kind of thrown at the reader. then there were pages and pages of blither about how everyone was feeling after the discovery. things that didn't exactly square with the beginning of the story. i gave it three stars for the potential this story held.

[Angie Holden · Rating 4 out of 5]

This book totally delivered the eerie, locked-room vibes I was hoping for. The setup hooked me right away. Of course, nothing ever stays perfect for long, and I loved how the tension slowly crept in. Strange noises, missing items, that creeping feeling of being watched… it all built up in a way that kept me turning the pages.

I really enjoyed the alternating perspectives, especially the chapters from the “unwelcome guest.” That added an extra layer of suspense and made me second-guess everything and everyone. The pacing was steady, and even though it’s on the shorter side, the story didn’t feel rushed or underdeveloped. That said, I did see the twist coming before the reveal, and the ending felt a little quick. But honestly, I was so invested in the atmosphere and the creeping sense of dread that I didn’t mind too much. I flew through this book in a couple of sittings.

Thank you to Booksirens for an arc and my thoughts are honest and voluntary!

[Cheryl Eager · Rating 5 out of 5]

The Unwelcome Guest is a well-written, chilling read. We get to know the characters through the voyeurism of the unwelcome guest always lurking in the shadows. I found myself enjoying the observations of lives stripped bare of pretension when the characters were oblivious to anyone watching.

The slow-burning of the suspense kept me on edge and turning pages, waiting for the unwelcome guest to make a big move or make a mistake and get caught. The creepy things the unwelcome guest did were at times enough to give me chills while reading.

The reveal is satisfying, and I don't want to give anything away, but I sure am glad April read the "gold binder" cover to cover!

If you are looking for a great summer thriller, I highly recommend this novel.

[Jatin Zadoo · Rating 3 out of 5]

A book filled with suspense and mystery.

After reading fifty chapters of this book, I know the answer to the question: Who is the Unwelcome Guest?

If you love mystery and suspense, then you will enjoy reading this book.

The book teaches:

Your Social Media Posts can affect your daily life.

Jealousy is a real thing.

Love these lines from this book.

At any time and any place, someone could be watching you.

You can't test for something you don't even know is there?

Perfection, no matter how carefully crafted, always had its cracks.

It's too easy to misstep or lose focus when the mind is clouded with fear.

[Michelle DeVera · Rating 4 out of 5]

I enjoyed this book, I found the pacing to be quick and it kept me engaged, I read it in a few days. None of the characters were very likable, but that didn't bother me. I loved the setting and I thought the descriptions were great.
I am taking away one start because the twist in the end was somewhat confusing to me. In my opinion it did not seem to line up with the beginning of the book, and there was nothing in the end that tied that together.
Overall, I enjoyed this book and would read this author again.

I received an ARC of this book to give an honest review.

[Jen · Rating 4 out of 5]

I really enjoyed this locked-room vacation thriller! It’s the perfect read for summer. The writing was very intricate and descriptive. I loved the setting of the sprawling mansion on an isolated island. The tension and unease builds at a steady pace. I was surprised by the ending and it made me want to read it again to find the clues I missed!

[Christina Jones · Rating 5 out of 5]

The Unwelcome Guest pulled me in right from the beginning and I had a hard time putting it down. Well, except for at night when I was home alone and started hearing noises in my own house. She had me guessing right until the very end.

[Reader · Rating 5 out of 5]

This is a beautifully written and captivating story, that sucks you in right away at the first chapter. Great character development for each character throughout and keeps you reading to figure out the end. The last 100 pages keep you on the edge of your seat!

[Diana · Rating 4 out of 5]

**I received an advance review copy for free, and I am leaving this review voluntarily**

“The Unwelcome Guest” by Cori Nevruz was a tension filled, almost voyeuristic look at a family vacation. The story includes four brothers and three of their wives (youngest brother is unattached) and follows them on what should have been their dream vacation. The oldest brother, Jonah, and his wife, Crystal have rented an entire tropical island for the family to enjoy for a week. As one could guess from the title, the vacation does not go as planned thanks to an Unwelcomed Guest.

The family dynamics in this novel are a mess, but they definitely felt believable to me. The oldest brother, Jonah, and his wife, Crystal, are very well off. Crystal is obsessed with her image both in real life & online, which is fitting because she’s a supermodel. She is the one that found the island and planned the whole trip. Jonah and Crystal invited each of Jonah’s brothers but did not pay for the whole trip themselves. They expected the rest of the siblings to pay their own ways, except for the youngest brother, Will, who is not married and just recently graduated from college. Sean and his wife, April, are exercise and wellness fanatics who own a gym. Thomas and his wife, Ilma, are a teacher and librarian that work for a school. While the mansion on the island has a little bit of something for everyone, the trip definitely was financially straining for the less-well-off brothers. Even though it seems like Will got a great deal, since his portion of the trip was paid for (secretly), Crystal planned on using him as a chef on the trip… which did not sit well with Will.

What blew my mind about the family dynamics was just how different each of the wives were. They literally did not seem to have anything in common other than the fact that they married into the same family. I most closely identified with Ilma, who is an introverted bookworm. I felt bad for her because she was soooooo uncomfortable with being on this trip. She didn’t know the other wives very well, and what she did know about them seemed to drive her crazy. I did not understand why Crystal thought this reunion-style trip would be a good idea given how different the three wives were, but then again, Crystal also seems to be blissfully ignorant of the unpleasant things in life.

The thing that bugged me about this book was the fact that the antagonist was repeatedly referred to as The Unwelcome Guest. It’s literally like calling the bad guy, The Bad Guy, throughout the whole book. I fully understand the idea of keeping the true identity of the bad guy hidden (and actually I was shocked at the reveal!), but calling them The Unwelcome Guest, which is also the title, bugged me. That’s pretty much the only reason I gave the book 4 stars instead of 5. Well, that and I felt like the differences between the wives was overly extreme. If they were that different & the cost was that much of a big deal….why did everyone agree to go?

Anyway, despite those drawbacks I really enjoyed the book! I definitely would recommend it to anyone looking for a creepy novel to read in the summer!

[Shane Sturtz · Rating 4 out of 5]

I recently bought a signed copy of this book from Cori at a local book fair in Raleigh, and I'm glad I did.

What a great, intriguing read!

At first, I had to adjust to the thorough writing style, but it was a great journey that had the perfect level of description.

I quickly read this book and it felt like a combo of the game Clue and the movie Knives Out. The private island gave it an awesome feel and then the family of characters made it come together nicely.

I was thinking it was unrealistic that no one could pick up on the unwelcome guest disrupting the house- kind of like what happens in a scary movie, when it becomes too obvious, but boy was I wrong!

I thought it was an extra character who was the unwelcome guest, but it was Will all along. Or was it?

All of the signs that April uncovered make sense, and we the reader saw the evidence unfold in real time. But who killed Fred?

And what about the Ferry Captain? That wasn't totally clear, unless I missed it.

Will could've hated his brothers AND there could have been another unwelcome guest. Both could be true, I think.

I didn't see the end happening the way it did. I figured the unwelcome guest would have been confronted by one of the brothers, but instead, Will was behind it all, supposedly.

A good quick read that was fun at the same time. Modern and easy to follow, and a little spooky and uneasy at the same time.

I'll have to read another book by Nevruz!

I didn't even touch too much on the characters, but I feel like each were unique and enjoyable (and annoying at the same time) to follow along

[Blaiz Ferrel · Rating 4 out of 5]

Twisty, Creepy, and Full of Hidden Secrets

I LOVE a mansion with hidden tunnels- don't we all?? and this one totally delivered. The Unwelcome Guest was a fast-paced, eerie read that kept me hooked. Not sure why people say it’s predictable—because that ending? Completely caught me off guard!

At times a bit is going on and a few characters to track, which got a little chaotic at times. But the creepy vibes, escalating tension, and isolated island setting made it worth it. Think: dream vacation gone full-blown nightmare. A chilling escape for fans of locked-room suspense.

The Unwelcome Guest
Four brothers and their wives reunite for a long-awaited getaway on a secluded private island. Their rented mansion is pure luxury—It's meant to be a time to relax and reconnect.

But unease creeps in. Strange noises echo through the walls. Personal items vanish. Shadows seem to move on their own. What starts as minor disturbances quickly escalates—accidents too precise to be random, a growing sense of being watched.

Cut off from the outside world with no cell service, no internet, and no return boat for days, the group begins to unravel. Because someone is in the house with them—hidden, silent, and waiting.
The dream vacation has become a deadly trap.

[Lupita_333 · Rating 5 out of 5]

This chilling story involves 4 brothers and 3 of their wives (one brother is single) who go on vacation to a mansion that’s located on an island. What was supposed to be a relaxing destination soon turns into them getting targeted by a secret guest that puts their lives in danger with the wives being the main targets. They have no way of escaping and no one is able to help them.

I loved everything about this story. From the eire setting to the mysterious man that some of the charters would see for brief seconds and the different ways the characters were being targeted had captivated me from the beginning to end of this story. I really liked how we were able to also see into the perspective of the “unwelcome-guest”. Their thoughts were sinister and creepy. It was so frightening how all those things were happening with none of the characters having a way of knowing who it was until it was revealed. When the “unwlecome-guest” true identity was revealed my jaw actually dropped from how shocking it was. Their reasoning behind why they did all this was what was so surprising and unexpected.

Thank you BookSirens for the ARC in exchange for an honest review.

[Valerie Ruiz · Rating 4 out of 5]

I really liked this one. At first, I wasn’t exactly sure what kind of thriller I was walking into. The title had me thinking there would be some creepy stalker or haunted house situation, and while there are definitely unsettling moments, it’s the emotional tension that truly delivers.

It starts off a little slow, but once things start unfolding, I couldn’t look away. Every time I thought I had someone figured out, the story shifted and threw me off. Cori Nevruz does such a good job of building that slow, creeping dread that gets under your skin. The main character’s mental spiral felt so real, and it made me question everything around her.

I also loved that this wasn’t just about fear or danger. It was about grief, trauma, and how the past doesn’t stay buried forever. The ending left me sitting there like, wait… what just happened?

If you're into domestic thrillers that build slowly, mess with your head, and make you question who you can trust, give this one a try.

I received an advance review copy for free, and I am leaving this review voluntarily.

[Patricia]

I love a good locked room (island) thriller!

It starts out as a sort of family reunion with four brothers and their wives. The setting is luxurious and with one of the brothers (Will) taking the lead on doing all of the cooking and cleaning up, there is plenty of times for the others to relax. But there are some funky dynamics going on (as expected). There are a lot of strange things happening, but most are attributed to Thomas, known for his pranks.

But the "unwelcome guest" has gotten his/her hands on the binder that contains the secrets of the house, and we get to see the thoughts behind their plans for this family, which ramps up the creep factor.

Thanks to BookSirens for an advance reader's copy. I enjoyed this new-to-me author and will be checking out some of her previous books!

[Heather · Rating 3 out of 5]

The Unwelcome Guest by Cori Nevruz is a perfect summer vacation read! It's quick, easy, and will keep you engaged throughout.

Four brother and their wives decide to spend a week-long vacation on an island. What starts out a pleasant family getaway filled with laughter and love soon turns into their worst nightmare. Seemingly accidental events start taking place, progressively getting more dangerous. Everyone is on edge and suspicious of each other. But can they solve the mystery of the unwelcome guest before things become deadly?

This is a locked room suspense novel that clearly transports the reader into the atmosphere of a beautiful and sunny local that soon turns dark and ominous, showing just how dangerous an isolated island getaway could be.

I received an advance review copy for free, and I am leaving this review voluntarily.

[K · Rating 2 out of 5]

Thanks to BookSirens for the ARC. I love this premise and setting - I've read many a good thriller set on an island. It started off strong, and I was fully engaged with the story, but if I'm being honest, it felt like the author changed their mind about whodunnit partway through writing. Some of the earlier aspects of the book felt illogical after reading the reveal, and even the reveal itself seemed to happen accidentally before the story's climax. I also found the narrative flow a bit disjointed, and sometimes I had to read a sentence multiple times to try to figure out what was going on. Finally, I felt that the way the unwelcome guest referred to the different members of the family was too on the nose and it didn't really work for me.

[Jennifer Spaulding · Rating 3 out of 5]

I received an advance review copy for free, and I am leaving this review voluntarily

I really enjoyed this thriller! I felt like the plot progressed well and always kept me on edge! I felt like the Unwelcome Guest was a little predictable but I was still torn between a couple of different options and didn’t feel confident in my guess until close to the end. The ending did still throw a nice twist in that threw me off! Some of the inside thoughts of the Unwelcome Guest seemed a little intrusive and grotesque and I wasn’t sure how much that contributed to the story as I was reading, but in the end it kind of helped. I felt like those could’ve been left out or not played up quite as much though. All in all, I really enjoyed this thriller and it was a great quick read!

[Trish · Rating 3 out of 5]

A chilling premise, a gorgeous yet isolating private island, and multiple POVs set the stage for what could have been a truly gripping thriller. While I loved the atmosphere and the tense moments that pushed the story forward, I found the plot a bit disjointed and the big reveal... underwhelming. I figured out the "who" early on, and the so-called unwelcome guest didn’t quite deliver as a convincing villain—but ironically, they were the most entertaining character! 😆

Still, if you're looking for a fast-paced, stress-inducing island mystery with a quick payoff, this is a speedy read that might be worth the trip. Just don’t expect all your questions to be answered.