Riccardo is a writer desperate to get past his writer's block. One day, a stranger shows up at his door to tell him that his grandmother has died and left Riccardo both her home in Milan and her renowned butterfly collection. Considering he is out of money, Riccardo travels to his new home, hoping the change will break his writer's block and help him survive. The house is not what he remembers; the butterflies strike a menacing tone, and his grandmother's odd friends always seem nearby. As he explores the house, he discovers his grandmother's journal, and what he finds within might not only be the answer to her death but might be what he needs to inspire his book. The key is making it through all of this alive.

This is not your typical horror novel. This one creeps up on you. Filled with secrets, magical realism, and gothic terror, this novel captures the monstrous side of humanity and will leave you reeling towards the end of this story. This one will haunt me for quite some time.

This was a fun gothic horror! I flew through this -- it was very easy to pick up and read. It did have some slow parts that could have been edited it, but overall I enjoyed my time with it! Thanks!

A mysterious stranger shows up at Riccardo’s apartment with some news: his grandmother Perihan has died, and Riccardo has inherited her villa in Milan along with her famed butterfly collection.

The struggling writer is out of options. He’s hoping the change of scenery in Milan will inspire him, and maybe there will be some money to keep him afloat. But Perihan’s house isn’t as opulent as he remembers. The butterflies pinned in their glass cases seem more ominous than artful. Perihan’s group of mysterious old friends is constantly lurking. And there’s something wrong in the greenhouse.

As Riccardo explores the decrepit estate, he stumbles upon Perihan’s diary, which might hold the key to her mysterious death. Or at least give him the inspiration he needs to finish his manuscript.

But he might not survive long enough to write it.

Overall: ⭐️⭐️⭐️⭐️/5

Thank you @netgalley for the gifted book.
When I signed up for this ARC I didn’t know what I was getting myself into. I really didn’t even read the synopsis, I just simply picked it because the cover and name sparked my curiosity.
Oh boy! This book is something, I don’t know what it is but it was definitely something else. The ambiance, the pace, the characters, the ominous feeling are all there to make you feel like something bad is going to happen, Riccardo, the main character knows it and you as the reader know it too and on top of that you will feel helpless because there’s nothing you can do to help.
That’s exactly what this book is, a sensation of impending doom that cannot be stopped.
Additionally, this book reiterates that monsters don’t always look like one and that people would most certainly hurt and destroy something beautiful and magical either for profit or to achieve what they need. The real monster is the one that hides its real self behind good intentions.
This book reminded me of a movie that I remember creeped me out when I watched it, The Skeleton Key. It was a good scary, suspenseful flick.

Thank you net galley for this arc, it was amazing! I enjoyed this so much, I can't wait for a physical copy to be released so I can get my hands on it. I rated this book a 4.5 stars.

Thank you to Netgalley, Harper Collins, and Yigit Turhan for this lovely ARC!

Riccardo, our heroic protagonist, learns that his estranged grandmother has died and he has inherited her estate. When he goes to Milan to claim what is his, he learns of a horrific story involving his grandmother’s community and a creature with magical powers.

This was an interesting story about complex familial relationships. I really liked the descriptions in this book. Yigit paints a gorgeous, atomospheric picture of Milan. The ending of this story was shocking to me, but I won’t ruin it for anyone!

Must read for anyone who loves gothic horror!

Their Monstrous Hearts by Yiğit Turhan is a creature of creature features. And while it’s disheartening the words ‘struggling’ and ‘writer’ are always married in sentences, here we are: Riccardo has severe writer’s block. He’s stretched his deadlines, his agent, and his emptying pockets to conjure his latest work. That is, until the death of his beloved grandmother left him with full ownership of a villa in Milan and her renowned butterfly collection. When he happens upon his grandmother’s diary shortly after attending her funeral, Riccardo thinks he’s struck gold, but as any seasoned reader of gothic horror will tell you, there’s always a madwoman in the attic. This was a story that had many unique elements and perspectives attached to it. I found it quite interesting. The performers for this audiobook really helped keep me immersed in the narrative. There were many parts that I feel would’ve hampered my “traditional” reading of the book, so I am grateful NetGalley and Harlequin audio offered me an eARC of this work.

Thank you, NetGalley and Publisher for this ARC. This book had all the elements of a horror story that I love ! It was atmospheric and had Gothic horror, elements. I thought the plot was unique and I liked the author’s writing style and character development too. It was a little slow for me, but the ending had amazing twist in terms. I would truly recommend this book and I’m looking forward to more books from this author!

Thank you, Yigit Turhan NetGalley, for the ARC. I leave this review voluntarily and happily. Also, thank you publishers for your hard work!

Im going to start off and say this wasn't exactly horror in my mind. It definitely was atmospheric, creepy, and definitely a mystery at times. There is also the element of the magical and fantasy here and there. Even so, I really enjoyed how this story turned out. Definitely didn't see how it was going to end nor the twists that happened. The details are very beautiful, and just all the butterflies use is definitely something i haven't seen. I really enjoyed it. I got to learn about different kinds of butterflies throughout the book. There is death, mystery, and all sorts of things going on in this book. You'll enjoy going through the journey like the main character does. Or you might not.

A stranger comes and tells the main character his grandmother is dead. He leaves the life he knew and moves back to the home he lived in when he was a child. Things seem strange and dark. Things change once he finds his grandmothers diary. It outlines her life and what happened till her last moments. What happened to her? What's going on with the people in this house, and what dark secrets are going to be found within the pages of the diary? Read and find out.

Like I said before, this wasn't really horror for me, but i did enjoy the journey it took me on. The murder and the mystery around it all was definitely what kept me locked into the book. Not only that, but the mythical and fantasy aspect surrounding it as well. Also, I loved the butterfly and all surrounding that.

Never trust the butterfly

This book is one wild ride! It's an atmospheric, slow-burn journey that’ll keep you on the edge of your seat, even if you're not the biggest fan of horror. The story kicks off when Riccardo, a struggling writer, inherits his grandmother's villa in Milan after her mysterious death. Of course, he's hoping for some inspiration and maybe even a little cash, but when he gets to the villa, nothing is as it seems.

The house, once grand, has fallen into disrepair, and those butterflies in glass cases? They're not as charming as they sound. The more Riccardo digs into his grandmother's past, especially after discovering her diary, the more questions pop up. What really happened to her? And what’s up with the creepy vibe that’s creeping through the entire villa?

The pacing’s a little slow at times, but trust me, the last part of this book will leave you shook—that twist is one you won’t see coming. It’s eerie, it’s haunting, and it’s definitely not your average horror. If you're into stories that mess with your head and keep you questioning what's real, then you definitely need this on your TBR.

Big thanks to NetGalley for the ARC in exchange for my honest opinion!

This book is unreal!

For a majority of the book, it reads like historical fiction. With dual timelines, it is captivating and suspenseful. It keeps you wondering where it all leads. The final 20% or so is twisty and absolutely unreal. The final 5% slaps you in the face and is just WOW! I did not see that ending coming.
A very s l o w burn horror story indeed.

This is unlike any other horror novel I have ever read, and it's very good. I will never look at any butterfly the same way again.
I recommend everyone who enjoys a great gothic horror story to read Their Monstrous Hearts when it's available.

This was one of the creepiest books I've ever read! I truly could not read it fast enough- I've never needed to know what was going on more in my life. It's best to go in blind.

Twenty year old Riccardo is writing his first book, and things are not going well. He is struggling with writer’s block and stalling for time to get something to his agent, while unpaid bills are accumulating at a rapid rate. When a stranger shows up to inform Riccardo that his estranged grandmother has passed, and he has inherited her villa in Milan, he thinks it might just be the opportunity he needs to bounce back financially and find the inspiration he desperately needs for writing his book. Riccardo soon finds that things seem strange at the villa and he discovers a manuscript written by his grandmother, which he hopes will give him answers to her death. As Riccardo delves into Perihan’s manuscript, a haunting horror begins to unfold, and he must decide if Perihan’s story is fact or fiction, in order to survive.

Their Monstrous Hearts ended up being a read in one day book for me, because I couldn’t put it down without knowing how the story ended. The book is told from Riccardo and Perihan’s POVs, with most of Perihan’s part of the story told as flashbacks. I was definitely interested in Riccardo as a character, with his struggling writer persona and estrangement from his family, but Perihan is definitely the dominant character. We see her struggles as the youngest in a family full of daughters in Turkey, and the drive that develops during her younger years, that motivates her character throughout the rest of story.

The pacing of the book is on the slower side, as most of it focuses on Riccardo reading Perihan’s manuscript. There are some horror elements interspersed throughout the first part of the book, but the majority of the horror exists in the last 30%. As a TRIGGER WARNING, there are graphic scenes depicted of child death in Chapter 21. I did feel like this part of the story didn’t fit in, and could have definitely been left out without affecting the rest of the book.

I really enjoyed the butterfly imagery, and how insects can be beautiful and terrifying at the same time. And Turhan does an excellent job of addressing the true monster/monsters in the story. I was very surprised by the ending, because it delivered a great horror twist, that I did not expect. It was definitely worth the slow burn horror build up!

If you love dual POVs, unexpected villains, shady side characters, and surprising horror twists, then I would definitely recommend Turhan’s first English language debut novel.

The dual timeline is still a relatively interesting approach, and overall the story was well-paced, but at times, it felt bloated, like a student using a thesaurus to pad the word count so they didn’t get marked down on an assignment. The synopsis of a struggling young writer being surprised by the gift of a dead grandmother’s gothic estate (not to mention the gorgeous presentation of the novel itself) set high expectations for me, but unfortunately the writing didn’t live up to them. 1.5 rounding to 2 stars

I liked the dual timelines and the cover! The author is talented, but the story was too slow for my taste. I need more action I think to keep me interested for the long haul.

I was interested in this setting, story, and characters, but the writing was incredibly amateur in my opinion. It was flat and uninteresting.

First off, the cover of this book is absolutely stunning! It’s giving creepy gothic vibes which I absolutely love! It brings out a lot of character in a book and is what drawn me to it.

Thank you to The hive and @harlequin books, htp books for gifting me this copy! I truly appreciate it and will definitely be reading more from this author in the future.

Who would have thought an author would make butterflies sound creepy! Literally gave me goosebumps as I was reading and that’s how you know the author done something right writing this book 🙌🏼🦋

This story takes place in Milan (which I love btw) and you have your MMC Riccardo where he is inspiring to become a writer but is struggling with it and he receives strange news that his grandmother passed away and finds out he inherits her villa in Milan. He hasn’t been back to her villa in a long time and remembers it being luxuriant especially the butterflies in the glass cases. Perihan his grandmother was obsessed with butterflies.

He then discovers a manuscript while he is at her villa that is labeled to him and reads it. The manuscript unravels some mystery and secrets to his grandmothers creepy butterfly collection that identifies some dark spots of eternal life and magic of monsters. It leads him down a path unexpectedly and starts to experience weird things in the house. With his journey reading more into the manuscript, he learns more about these butterflies where you can desire to extend your life for eternity. You die and come back to life and a butterfly will come and find you to resume your life. I found this part in the book interesting especially reading about the teardrops with the conversation with Fumito.

This is great for those who are into gothic/horror. The writing felt a bit repetitive but was still overall great and felt a bit slow for me at first but it definitely picked up and kept you on your toes waiting for that next twist to happen!

With writing that is both dark and vibrant, this is definitely an author to watch! I loved the layer upon layer of mystery.

Inheriting an old house is a trope I fall for every time, especially when there is a creepy factor. We also get this really ominous butterfly collection that I found incredibly intriguing. But, it is the diary belonging to the woman who owned the house, our protagonist’s grandmother that I really vibed with!!!

I highly recommend this one!

I really tried to enjoy this book, the premise and cover really drew me in. I struggled my way through it for weeks on and off because I couldn’t immerse myself in the book. The writing style wasn’t really my cup of tea and at times felt like I was reading something written by a robot.

I loved the beautiful cover for Their Monstrous Hearts and it sounded like an intriguing premise, so I was excited to request and read it!

When Riccardo learns he has inherited his grandmother’s mansion and butterfly collection, he hurries over to Milan. However, when a mysterious diary appears and his grandmother’s friends seem to be holding secrets, he starts to wonder what legacy he has inherited.

Their Monstrous Hearts uses a narrative technique that I’ve seen used quite a lot in my 2025 reading – present day narrative interspliced with diary entries from the past. Riccardo is reading the diary in the present day which tells the story of his grandmother’s life and her adventures with the butterflies. This technique fell a little flat for me, as most of the present-day text is rendered obsolete if Riccardo had just read the diary a little faster and in one sitting. I also found that the chapters alternated without any real signposting that you were now in the diary entry – having them in italics or including chapter headings would have really helped with this.

I loved the premise of the book - without giving too much away the butterfly aspect and what people would do to hold on to the power was unusual and interesting. I really enjoyed the ending, and this really saved the book for me. However, I found the writing in the middle quite repetitive and slow. I didn’t really feel any proper stakes or tension in the present-day text and the flashbacks took too long establishing character rather than moving the story along. Speaking of characters, I also feel that we didn’t get to know Riccardo as much as I would have liked and so I didn’t feel particularly invested in his story.

Overall, Their Monstrous Hearts is an unusual and interesting premise, but it’s writing style sadly let it down. Thank you to NetGalley & Harlequin – Mira for the chance to read the ARC in exchange for an honest review.

When a stranger brings news of Riccardo's grandmother dying, Riccardo discovers that he is now the inheritor of her Milan villa filled with her collection of butterflies. Riccardo, who is a struggling writer, chooses to go to her villa where he finds his grandmother’s diary.

The more Riccardo reads from the diary, the more questions he ends up with. While hoping for inspiration on his book, he also dives into exploring his grandmother’s death.


This book had the makings of a great story. I loved the premise, the atmosphere, and the setting. I always love books set in Italy. I also appreciated the uniqueness to incorporate these butterflies into the horror. Unfortunately, I felt that the writing and structure fell short for me. I found myself a bit confused in the middle of this story and the writing wasn’t the most advanced. The beginning and end were the strongest parts of the story, but I got a bit lost in the middle and it was hard for me to keep interested in this book at times.

I read somewhere that this is the author’s first book written in English which makes me less concerned with the writing because I know that this is miles ahead of anything that I would be able to write. I think with some more practice, this author can really polish off the bumps in prose. For being his first English novel, I’m actually pretty impressed. I’ll definitely read more books by him in the future.

Thank you to NetGalley and the publisher for the arc. All opinions are my own.

TW: suicide, child death, gore, violence, animal death, injury detail, blood, body horror