Obsession : When Does Caring For Someone Become A Step Too Far

by Lucy O'Callaghan

When a woman’s desire to help those who need it most sparks a dangerous obsession in one man, will she be able to see what’s right in front of her?

She needs to help. He needs her help. It’s that simple… or is it?

Since losing her brother to suicide five years ago, Rachel has thrown herself into her job, supporting men in getting back to work and rebuilding their self-esteem. Men like Peter—an ordinary man, seemingly down on his luck, but hiding a dependency on painkillers and alcohol.

Peter mistakes Rachel’s kindness for something more and believes they are destined to be together—even if she needs a little help along the way to realize it.

While Rachel is consumed with helping others, she is blind not only to Peter’s growing infatuation but also to family secrets emerging from the past.

Will Rachel recognize Peter’s obsession before it is too late?



Praise for Lucy O’Callaghan"I raced through, deeply invested in the characters. Loved how it touches on different ways of being obsessed." — Mary Watson

"Tense, taut and terrifying – a page-turner that also tackles important issues. I read it in one sitting!" — Edel Coffey

"A deliciously sinister compelling tale of secrets, infatuation and delusion." — Michelle McDonagh

"A compelling and absorbing interrogation of stalking, deftly handled by a skilful author" — Andrea Mara

Genres: Psychological Thriller

386 pages, Kindle Edition

Published March 31, 2025

Reviews

[Leona · Rating 5 out of 5]

This was another brilliant read by Lucy O’Callaghan and I was hooked from the prologue. As the title says this was certainly a book about obsession. Rachel works at The Hub, a place where men can attend and learn back to work skills and talk with counsellors about any issues they may have. However one of the men Peter develops a creepy obsession with Rachel and convinces himself they should be together, even though Rachel is happily married with two children. What follows throughout the book is a dark and growing infatuation that at times sent shivers up my spine. We are also introduced to Grace who plays a part in the story , each chapter is alternated between the POV’s of Rachel, her husband Conor and Grace. How is Grace connected to all this? I really love these types of domestic thrillers and this one was certainly no exception. Obsession was for me one of those reads that I found difficult to put down and after each chapter I just wanted to read more. My thanks to Booksirens, Author Ruth O’Leary and Poolbeg Publishers for the opportunity to read an early review copy . This review is my own honest opinion.

[Bianca Ellerkamp · Rating 4 out of 5]

In the book we follow two storylines. The first is about Rachel O'Donnell. After her brother committed suicide she changed jobs, instead of childcare she switched to supporting men in getting back to work and rebuilding their self-esteem. She is married to Conor and together they have two children. Because of her dedication to her work she works more and more hours and unconsciously neglects her family. This with all the consequences. In her work she comes into contact with Peter, a man who was left by his wife after he lost his job. He is no longer allowed to see his children due to excessive alcohol and pill use. He develops an obsession with Rachel, in his head she is just as crazy about him as he is about her. But is that true?
The second storyline is about Grace McHugh, a young woman of 21. Just before her mother dies from cancer she is told that her father has no idea of her existence. In a letter she receives after his death, her father's name is mentioned and she immediately starts searching. Will she find her father? What will he say about the fact that Grace is his daughter? Slowly but surely, both storylines come together and intertwine.
The plot is well developed and contains a few twists. Because we follow the story from different angles, there are few surprises left, but that does not detract from the reading pleasure. The storylines come together halfway through the story and run through each other towards a slightly exciting and beautiful ending.
The characters are very well portrayed, making their emotions clearly palpable. The author has managed to make me annoyed by Rachel's naivety and Peter's narcissism.
The tension that runs through the entire book is mainly subcutaneous, it is not nail-biting tension, but that something is going on and is going to happen is clearly palpable.
Obsession is a well-developed, subcutaneously exciting book that provides a number of pleasant hours of reading.
I received an advance review copy for free, and I'm leaving this review voluntarily.

[Kelsey · Rating 3 out of 5]

Rachel needs to help, and Peter needs her help. It’s that simple… or is it?

_________
The writing was simple, and it was a good popcorn read. It follows two plot points, but the main one I found to be slow going and repetitive. And then once everything came to a climax, it seemed a bit rushed. I don’t know, personally I wish the resolution took a little longer.

And the title is Obsession, while it was creepy, I kinda wish that it was a little creepier and more drawn out in that aspect. But that’s just a me thing.

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

[Stormy Shadows · Rating 3 out of 5]

3.25
This was alright. I really got annoyed with Peter omg I wanted to throw him away lol. This isn’t the worst thing I read and the ending really was interesting. This is about a stalker and it follows two different story lines. One is about Rachel and Peter who he’s the creep and she works with him and the other is of Rachel’s husband Conor and a woman named Grace who is from his past and everything comes together by the ending but really not my favorite. Could have been way more adventurous and creepy and just all around more fun. That’s just me though.

[Sharmaine · Rating 5 out of 5]

This book. Wow just Wow. had me hooked from the first chapter. Didn't want to put it down and had me guessing on every page. i never suspected the ending and i'm usually a person that can suss out what's going to happen before i've read it but i didn't with this at all.

the book was well written, loved the characters and they were described well and clearly. i knew exactly who each person was and when during the book. loved this was gutted when i had finished it.

i received a copy of this for free and i am leaving this review voluntarily.

[Diane Elizabeth Taylor · Rating 4 out of 5]

A compelling book of unreciprocated love turning into obsession.
Haunted by her brother's death, Rachel just wants to help others. Pete convinces himself he and Rachel will be together, and when things start falling apart for him, his obsession turns dangerous.
Grace's search for her father adds another layer of emotional depth to the story and I'm grateful to BookSirens for the ARC. This is my honest review.
The characters are well fleshed out, each with their own faults and agendas, making them relatable.
The ending is all tied up neatly, resulting in an engaging, well written novel that I'd recommend.

[Ita Roche · Rating 5 out of 5]

I have often heard it said that love will take you places a sane mind would never go, and in this cracker of a read by O'Callaghan, that exact scenario is played out to perfection.

A psychological thriller in which unreciprocated love warps Peters grip on reality.

Peter’s obsession with Rachel and his need for them to be together leaves him reading way too much into a kind gesture, a simple smile or a wave.

Rachels obsession with helping people after her brother’s death is also all consuming and renders her distracted and therefore blinded to Peters growing fixation to grab moments with her.

All the ingredients for a perfect storm resulting in disastrous consequences.

I am dyslexic and a slow reader, but I flew through this book totally immersed in very well-rounded characters, short sharp chapters and a really gripping plotline of which Peters story is just one. I’d go so far as to say, if you’ll excuse the pun – that I am obsessed with Obsession.

Highly recommend and cannot wait to read more from this author.

[Lynda · Rating 3 out of 5]

Obsession was an easy read and I tried to enjoy the storyline but honestly I felt it may have just taken a bit too long to get to the main part of the story.

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

With Rachel and Peter being the main characters I just felt like we were rereading the same things over and over. Driving down the road, sitting watching for Rachel, waving to Rachel, seeing Rachel at the shop. Peter’s drinking and pill popping just didn’t do enough to get the feeling of danger for Rachel. I wanted to read more action.

I liked getting to know Grace and seeing her unite with her father. This storyline was genuine. I’m glad that it worked out for Grace getting to meet her dad and eventually meeting Rachel and then her new siblings.

I found a couple errors in the copy I received as well but understand that these things happen.

[Ruthie Mckinney · Rating 3 out of 5]

He’s obsessed with her, so obviously she’s obsessed with him too, right? Well, we’ll see. Obsession caught my attention right from the start. There are a couple different point of views but it’s not hard to follow. I did enjoy it and was eager to find out how it ends. There is some family secrets and drama involved in the plot as well. I think there could have been more background information on the antagonist and more character development. We heard from the antagonist point of view quite a bit but not at the end and that would have been nice. There is no big plot twist as some thriller readers look for so that may be disappointing for some but I typically don’t care either way. I give it an overall rating of 3 stars and would read another of the authors books. I received this book free as an advance reader copy and I am leaving this review voluntarily.

[Caroline Rowan · Rating 4 out of 5]

This is one of the best slow-build tension books I have read in quite a while. Lucy O'Callaghan creates a story that lays out just enough detail in each chapter to leave you waiting with baited breath to find out what is going to happen next. The description of Peter's alcoholism and growing obsession with Rachel ratchets up the tension gradually until you are completely hooked.
A book that will make you rethink every interaction you have ever had with strangers.

Can't wait to read her next book.

#GalwayAuthor #RecommendedRead

[Caroline 'relaxing with my rescue dogs' · Rating 3 out of 5]

This could have been a lot more with the tension and the characters that were there. I found it flowed and it was an easy read but I felt disappointed and wanted more from the read. The story was told from different POVs and so it unravelled and hints were given throughout the book. The ending tidied everything up but felt rushed.
This is not going to put me off reading more by this author.

[Fleury · Rating 4 out of 5]

This is a very very enjoyable book. Great characters, had to love Rachel, Grace and Conor.
Totally disliked Peter, who was probably the intention of Lucy O'Callaghan.
This is the first of Lucy O'Callaghan's books I've read.
I'll certainly get her other book (I think it's her debut) "The Lies Beneath"

[Shelia · Rating 5 out of 5]

I was lucky to get to read an ARC of this book. It was fast paced and easy to follow. So many twists that I didn't see coming. How far will Peter go to get Rachel to notice him? Can Grace find her father? Get your copy on March 31!

[Kristi Bloedorn · Rating 4 out of 5]

Easy to read and moved at a nice pace. The author developed like able characters. The story made sense and all tied together. I would definitely try this author out and would read more of her work.

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

[Karen Fleming · Rating 5 out of 5]

Thoroughly enjoyed this dark thrilling read. Lucy O'Callaghan has captured the menace of being stalked perfectly . Vibrant characters and twisty plot will keep you guessing until the end. I'd highly recommend this book.

[Burma Turner · Rating 4 out of 5]

This book was fantastic! Sometimes you can be too nice and not see what others see. Well-written and intriguing.

[Mari Noonan · Rating 5 out of 5]

I really enjoyed this well written page turner. The situation is very believable and the tension keeps escalating to the final page.

[Caroline Croezen · Rating 5 out of 5]

Superb. An eerie page turner that's so creepy. Absolutely flew through it.

[Eilish O · Rating 5 out of 5]

Absolutely loved this book! Such a crazy story with insight into the mind of a stalker. I really loved this read a real page turner!

[Oonagh Considine]

Not into this book at all

[Amy Walsh · Rating 4 out of 5]

Obsession
Lucy O' Callaghan
Read and Reviewed: April 2025

This was the first book I've read by this author. A friend recommended it to me so I moved it to the top of my TBR list straight away and it didnt disappoint.

The blurb of this one sounded fantastic and Lucy was certainly well capable of keeping me engaged and gripped throughout this mildly creepy domestic thriller.

The book is told via two seperate storylines.

The first storyline follows the POV of Rachel, who works at 'The Hub' - a place men can attend as a social outlet and to talk with councillors and/or fellow attendants to the club about any issues they are facing. A while back, after her brother commited suicide Rachel quit her job in childcare and started working at The Hub because she felt like she had failed at helping her own brother and she wanted to help other men. She is married to her husband Conor and they have 2 children together.

At her job, she comes into contact with Peter - one of the men at the club and the rest of her storyline follows his creepy obsession with Rachel.

In the second storyline, we are introduced to Grace, a 21 year old woman who's mother is terminally ill and dying in hospital. Just before passing away her mother tells Grace her father (who she has never known a thing about) doesnt even know she exists. The remainder of this storyline follows Graces search for her father...

The two storylines come together at about the halfway mark and intertwine answering all and any of our unaswered questions.

I won't say anything else cos I dont want to spoil it for anyone but Obsession was definately a different sort of thriller read. We see the story unfold from multiple different angles. It is not majorly fast paced and there is no nail biting tension as such bar a bit of excitement near the end - but it is still a read that I really enjoyed.

The characters were so well developed, each with their own traits and faults. The writing flowed nicely towards an exciting and well tied up ending. It wasnt as creepy as I was expecting - defo a slower burn story but its one I really liked and will definately be recommending it.

I look forward to reading some other books by this author.

4 stars

⭐️⭐️⭐️⭐️

[Cynthia Jackson · Rating 4 out of 5]

Thank you to Book Sirenes and Lucy O'Callaghan for the eARC! This gripping thriller delivers the perfect balance of fast-paced action, emotional depth, and unpredictable twists. I loved how the story unraveled, only to come together in a way that kept me hooked until the very end. A compelling and thrilling read!