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The Underground #2
Unbreakable Thread
Rainey Collins thought she knew who she was—until the lies and secrets of her past began to unravel everything. Now she’s barely holding herself together, haunted by memories she can’t escape and convinced that the one man she loves will only suffer because of her. Pushing Max away feels like the only way to protect him.
Max Cano never wanted the spotlight, but his rising boxing career has other plans. Pulled between the demands of fame and the life he actually wants, he struggles to keep his footing—but losing Rainey is the one thing he refuses to accept. He won’t give up on her. On them.
But when someone they both trusted turns out to be their greatest threat, everything changes. Rainey finds herself trapped in a world she never saw coming, and Max has one mission—keep her safe. Through betrayal, heartbreak, and everything stacked against them, one thing remains: they have always had each other’s backs. This time is no different.
Unbreakable Thread is the second book in the Invisible String duet, part of The Underground Series.
Author Note:
Unbreakable Thread MUST be read in order. This book is a continuation of Invisible String.
Read in order
(Invisible String & Unbreakable Thread are a Duet)
Book 1: Invisible String
Book 2: Unbreakable Thread
Book 3: Coming soon
Max Cano never wanted the spotlight, but his rising boxing career has other plans. Pulled between the demands of fame and the life he actually wants, he struggles to keep his footing—but losing Rainey is the one thing he refuses to accept. He won’t give up on her. On them.
But when someone they both trusted turns out to be their greatest threat, everything changes. Rainey finds herself trapped in a world she never saw coming, and Max has one mission—keep her safe. Through betrayal, heartbreak, and everything stacked against them, one thing remains: they have always had each other’s backs. This time is no different.
Unbreakable Thread is the second book in the Invisible String duet, part of The Underground Series.
Author Note:
Unbreakable Thread MUST be read in order. This book is a continuation of Invisible String.
Read in order
(Invisible String & Unbreakable Thread are a Duet)
Book 1: Invisible String
Book 2: Unbreakable Thread
Book 3: Coming soon
531 pages, Kindle Edition
Published August 31, 2026
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Displaying 1 - 8 of 8 reviews
August 30, 2026
WHAT AN EMOTIONAL RIDE!
Heartbreaking. Poetic. Beautiful. Healing
I knew going in this was going to be an emotional roller coaster, and WOW was I was right. There were things I absolutely did NOT see coming. I’m not spoiling anything, but you might cry.
This was a heavy read, but in the BEST way. If you loved book one, you’re going to absolutely LOVE book two. It was phenomenal from beginning to end. I literally couldn’t put it down!
I think we can all see a little bit of ourselves in Sol/Rainey.
Her story really shows how important therapy is, but also that healing requires you to open up, face difficult things, and do the work, including learning to set boundaries. Boundaries can be incredibly hard to establish and even harder to use, but once you do, you realize they’re there for a reason. Sometimes protecting your peace and being able to say “this is my boundary” is an important part of healing, too.
And MAX!!! I NEED, NO WANT A MAX OF MY OWN !!
Every character in this story was incredible!
Heartbreaking. Poetic. Beautiful. Healing
I knew going in this was going to be an emotional roller coaster, and WOW was I was right. There were things I absolutely did NOT see coming. I’m not spoiling anything, but you might cry.
This was a heavy read, but in the BEST way. If you loved book one, you’re going to absolutely LOVE book two. It was phenomenal from beginning to end. I literally couldn’t put it down!
I think we can all see a little bit of ourselves in Sol/Rainey.
Her story really shows how important therapy is, but also that healing requires you to open up, face difficult things, and do the work, including learning to set boundaries. Boundaries can be incredibly hard to establish and even harder to use, but once you do, you realize they’re there for a reason. Sometimes protecting your peace and being able to say “this is my boundary” is an important part of healing, too.
And MAX!!! I NEED, NO WANT A MAX OF MY OWN !!
Every character in this story was incredible!
September 6, 2026
⭐️⭐️⭐️⭐️.5
Unbreakable Thread by J. Morales
Unbreakable Thread picks up right where we left off in the first book, and I was immediately pulled back into Sol and Max’s story.
I absolutely love J. Morales’ writing style. It flows so smoothly and is engaging from the very beginning. This book was a complete rollercoaster of emotions—you will definitely want to have the tissues ready! 😭💚
Sol and Max are everything. They are true soulmates, with a beautiful, pure love that endures so much throughout the story. Their connection is undeniable; they are constantly drawn to one another, and I found myself rooting for them every step of the way.
One of my favourite parts of this book has to be the found family. Leo, Drake, Xander, Pops and Mrs Debbie each bring something special to the story. I absolutely loved their interactions and the way their relationships developed throughout. They brought so much warmth, humour and heart to the book.
My only gripe is that I felt the book was a little too long. The miscommunication could have been brought to a head sooner, which would have helped the pacing for me. That said, I still thoroughly enjoyed the journey.
And now I’m impatiently waiting for Xander and Lana’s story! I can’t wait to see what comes next.
Thank you to the author for providing me with an ARC. This is my honest review and all thoughts and opinions are my own.
Unbreakable Thread by J. Morales
Unbreakable Thread picks up right where we left off in the first book, and I was immediately pulled back into Sol and Max’s story.
I absolutely love J. Morales’ writing style. It flows so smoothly and is engaging from the very beginning. This book was a complete rollercoaster of emotions—you will definitely want to have the tissues ready! 😭💚
Sol and Max are everything. They are true soulmates, with a beautiful, pure love that endures so much throughout the story. Their connection is undeniable; they are constantly drawn to one another, and I found myself rooting for them every step of the way.
One of my favourite parts of this book has to be the found family. Leo, Drake, Xander, Pops and Mrs Debbie each bring something special to the story. I absolutely loved their interactions and the way their relationships developed throughout. They brought so much warmth, humour and heart to the book.
My only gripe is that I felt the book was a little too long. The miscommunication could have been brought to a head sooner, which would have helped the pacing for me. That said, I still thoroughly enjoyed the journey.
And now I’m impatiently waiting for Xander and Lana’s story! I can’t wait to see what comes next.
Thank you to the author for providing me with an ARC. This is my honest review and all thoughts and opinions are my own.
Review of advance copy received from Author
J.Morales… has done it again!
What can I say about Unbreakable Thread is that it is going to be a wild ride with twist and turns!
I love the storyline and details so much emotions. It had my emotions in a chokehold for real! I threw my kindle, hit my car steering wheel, anger so much anger lol… J.Morales had me wanting to jump in the book ready to throw some hands!!! And she had me balling/ ugly crying.
I absolutely love this book! It will always have a special place in my heart forever! Unbreakable Thread is going to make you a boxing fan and wanting a man like Max! Cause who wouldn’t want a man that is protective, obsessed, that will go to the end of the world and back just for YOU! Because I know I definitely would love one
& “Rainey” just wow! What she went through was absolutely crazy! Luckily she had a wonderful and strong support system and when you get to that “beautiful part” you will know it when you read it you’re going to shout and say YESSS!!! Well for me I did.
Max and “Rainey“ what a beautiful story. They went through a lot together and separate it was beautiful to see the growth and lessons that they learned.
But J.Morales you broke me with this one! Thank you so much for allowing me to be a part of this journey and I can’t wait to see what else comes.
What can I say about Unbreakable Thread is that it is going to be a wild ride with twist and turns!
I love the storyline and details so much emotions. It had my emotions in a chokehold for real! I threw my kindle, hit my car steering wheel, anger so much anger lol… J.Morales had me wanting to jump in the book ready to throw some hands!!! And she had me balling/ ugly crying.
I absolutely love this book! It will always have a special place in my heart forever! Unbreakable Thread is going to make you a boxing fan and wanting a man like Max! Cause who wouldn’t want a man that is protective, obsessed, that will go to the end of the world and back just for YOU! Because I know I definitely would love one
& “Rainey” just wow! What she went through was absolutely crazy! Luckily she had a wonderful and strong support system and when you get to that “beautiful part” you will know it when you read it you’re going to shout and say YESSS!!! Well for me I did.
Max and “Rainey“ what a beautiful story. They went through a lot together and separate it was beautiful to see the growth and lessons that they learned.
But J.Morales you broke me with this one! Thank you so much for allowing me to be a part of this journey and I can’t wait to see what else comes.
September 7, 2026
I waited a year for this book, stayed up all night to read it, and was sadly disappointed.
Max Cano, the MMC - absolutely love him. He is such a great character and a wonderful pillar of strength for those he loves. He'll always be one of my favorite book boyfriends.
Rainey/Sol, the FMC - she's infuriating, even more so than in the first book. I understand that she's been through a lot and she's suffering from trauma and PTSD, but for half of this book she is such a waste of a character. Just like in the first book, she lets her insecurities get the best of her.
Good things about this book include Hector (Max's dad) finally becoming sober & staying that way, plus, the return of Drake. The story drags on and there are so many secrets between Max and Rainey/Sol that is gets cringeworthy.
Thoroughly enjoyed the first book, but this one is mediocre at best. It can't be read as a standalone.
Max Cano, the MMC - absolutely love him. He is such a great character and a wonderful pillar of strength for those he loves. He'll always be one of my favorite book boyfriends.
Rainey/Sol, the FMC - she's infuriating, even more so than in the first book. I understand that she's been through a lot and she's suffering from trauma and PTSD, but for half of this book she is such a waste of a character. Just like in the first book, she lets her insecurities get the best of her.
Good things about this book include Hector (Max's dad) finally becoming sober & staying that way, plus, the return of Drake. The story drags on and there are so many secrets between Max and Rainey/Sol that is gets cringeworthy.
Thoroughly enjoyed the first book, but this one is mediocre at best. It can't be read as a standalone.
September 12, 2026
I beta read this book and I loved every second. It was so emotional and touched every part of me, deep in my soul!
This is the perfect way to end this duet. It had so many plot twists, ones I never saw coming and they were so good.
The rage I felt towards everyone who tried to come between Max and Sol aka Rainey was so deep in my soul, my blood was boiling. Especially when Sol was just trying to find herself with all the memories flooding her head.
I loved that Drake returned, their reunion was so beautiful, I loved that he really stepped up again just like when they were kids and he protected them.
This is the perfect way to end this duet. It had so many plot twists, ones I never saw coming and they were so good.
The rage I felt towards everyone who tried to come between Max and Sol aka Rainey was so deep in my soul, my blood was boiling. Especially when Sol was just trying to find herself with all the memories flooding her head.
I loved that Drake returned, their reunion was so beautiful, I loved that he really stepped up again just like when they were kids and he protected them.
September 1, 2026
This an ARC review. Thank you very much J. Morales for the ARC!
This was a beautiful story. O my goodness, I was rooting, laughing and crying all the way to the end. Reading Max and Sol's story with a front row seat, the way the characters and story flows and evolve, pulling you in. I couldn't put it down.
Other than their love story being one of my favorite things of this duet (obviously), it is also the stories the other characters might be without actually spoiling what might come next.
Thank you very much! This was sooooo worth the wait.
This was a beautiful story. O my goodness, I was rooting, laughing and crying all the way to the end. Reading Max and Sol's story with a front row seat, the way the characters and story flows and evolve, pulling you in. I couldn't put it down.
Other than their love story being one of my favorite things of this duet (obviously), it is also the stories the other characters might be without actually spoiling what might come next.
Thank you very much! This was sooooo worth the wait.
Review of advance copy received from Author
4.25⭐️
I received this book as an ARC, and I'm leaving an honest review voluntarily.
Finally! The conclusion! So excited to finally see how this story ended and was kept wondering "what was happening next". The author does a good job of storytelling and surprises during the journey.
Happy to finally have their story finished and also sad for the journey they had to endure to get to their happily ever after.
I received this book as an ARC, and I'm leaving an honest review voluntarily.
Finally! The conclusion! So excited to finally see how this story ended and was kept wondering "what was happening next". The author does a good job of storytelling and surprises during the journey.
Happy to finally have their story finished and also sad for the journey they had to endure to get to their happily ever after.
September 6, 2026
what a wild ride!!!
I binged both books in a weekend, very little sleep was had (just a shame I wasn’t partaking in some of the activities gracefully worded in these books)… some severe twists along the way! It tore my heart out put it back piece by piece just to rip it to shreds again.
I binged both books in a weekend, very little sleep was had (just a shame I wasn’t partaking in some of the activities gracefully worded in these books)… some severe twists along the way! It tore my heart out put it back piece by piece just to rip it to shreds again.
Displaying 1 - 8 of 8 reviews