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Assassin's Heart #2

Loyal by Default: Assassin's Heart, Book 2

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Carter Reed is an assassin with a heart that only beats for one McKenna Smith.

In a perfect world, she would be the light to his darkness. Carter's world, however, is far from perfect. Which means McKenna cannot exist in it without a target on her back.

While he's away, Carter's enemies get close, and McKenna's life is threatened. In his quest to keep McKenna safe, Carter's world expands with revelations from his past coming forth into the present. Soon, he realizes time and place no longer matter because he's the only person who can keep McKenna safe… and she's the only one who can make him feel worthy.

If love is complicated, then theirs is an intricate web of complexity.

Audible Audio

Published February 18, 2025

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303 people want to read

About the author

K.C. Mills

197 books1,707 followers
KC Mills is an international bestselling author, speaker, and CEO. Ranked along with well respected authors, Mills has over 100 books which have hit number 1 bestsellers. She has proven herself as a leader in her industry with over 120 successful books written and published within a five year timeframe. She is committed to bringing exceptional literary works that offer a romantic twist, as well as subtlety veering away from the norm. She still however leaves you captivated by her stories, characters and always wanting more. Mills’ current focus is her cross over to the script writing arena where she will begin writing for some of Atlanta’s top production companies and the nation’s most notable television networks.

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5 stars
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Displaying 1 - 30 of 137 reviews
Profile Image for Rashawnda.
1,391 reviews1,139 followers
April 17, 2024
Did Carter and Kenni want to live in each other’s skin?! Or did they want to 🗣️LIVE IN EACH OTHERS SKIN??!?!!!!! I meannnnnn!!!!! It was the hip grabs and the shoulder kisses and the pulling into one’s side and the neck nuzzles for me!!! Carter and Kenni kept that same energy when it came to being obsessed with each other and I wasn’t disappointed at all! Loved loved loved them!!! 😩🥹🥰🖤

When Carter left Kenni in 24/3 we knew that man was coming back for her!! The word wasn’t right otherwise! That earthquake in NYC recently was a result of their worlds being unaligned 🤣🤣!! But no seriously despite her sad attempt to move on with Tevin and his goal to clean up the mess of his past first, 🗣️WE KNEW!! Due to Carter’s unintentional negligence, if that’s what we want to call it, his timeline of getting his woman back was significantly moved up and there was no hesitation in his thoughts or actions that delayed him snatching her up and protecting her by any means necessary!

Carters past, present and future decided to meet up and said let’s turn this man’s life upside down for a minute and did just that! I loved the deep dive into Carters life that we got and how everything came together for him in the end. I didn’t doubt him at all because he was definitely the black Liam Neeson putting his particular set of skills to good use! 😉

Listen!! If Carter was riding, Kenni was rolling 🥰and vice versa and I loved the entire dynamic of their relationship! Carter’s profession did not afford him with the opportunity of softness however the soft life he created for my girl was everything. There wasn’t a single thing Kenni didn’t want that he didn’t make a reality. From her mouth to Carter’s ears, it was just that simple!

It was the rooftop butterfly date for me 🍽️ 🦋
It was the art auction and meeting the artist for me! 🖼️ 🎨 👩🏽‍🎨❤️
It was Shadow for me! 🥹🩵
It was Carter getting the answers he deserved with Kenni by his side every step of the way for me!

Kenni was worrisome with her fifty lem questions but shiii if my man was a hired gun I would be asking just as many if not more because what you meeeaaaan you kill ppl for a living?!!? Because what do you meeannn you’ll be right back?! Is this a run to the grocery store right back or a “Succinylcholine” right back?! 😳😳😂😩😂😩

I wasn’t sure if we would get the same level of intensity this couple gave us in their novella but they didn’t miss a beat and picked up exactly where they left off! K.C. said they were worth the wait and not a 👏🏽 single 👏🏽lie 👏🏽was 👏🏽told!
Profile Image for Annette Williams.
1,197 reviews423 followers
July 20, 2024
“Do you need me?” She pulled back and her eyes met his. A sinister smile eased onto his face. “You’re my life support, Kenni. I need you.”

Carter and Kenni are officially my second favorite couple of 2024. The way these two loved and loved on each other was almost sickening. The subtle glances and touches between them and the way he crawled into bed to spoon with her after a kill had me totally swooning. Carter’s past plays a pivotal role in this book. It goes into great detail about his parent’s death and how he became an assassin. Honestly, I almost DNF’d this book because, I just wasn’t that interested in Carter’s past. But, the relationship and the love he and Kenni had for each other is what hooked my attention. ‘He kissed her shoulder and guided her closer. A few minutes passed and Carter felt her breathing level again so he reached for her left hand, slid the diamond on her finger, and softly pressed a kiss to her knuckle before his eyes closed and his breathing fell in sync with hers.’ I mean, how could you not want to experience this level of romance between two characters?!!! I may not have been a fan of the dumpster dive into Carter’s past but, I was 1000% invested in Carter and Kenni’s love journey. I appreciate K.C. Mills for keeping that same energy from Twenty -Four Three. The love and chemistry Carter and Kenni had for one another was just as apparent here and I wasn't disappointed one bit.
Profile Image for *Ebony I*.
1,415 reviews155 followers
April 24, 2024
Back to Love

Que Hi-Five's Never Should Have let you go...… 🎶And I'll be thinking 'bout you every night and every day' Cause in my heart I'll know (I'll know)
That I never should have let you go🎶

This song was the theme song for Carter. His lifestyle just was not suitable for love, but his connection was so strong with Kenni in the first book I knew that was not the end of their story and Book 2 did not disappoint. Carter was so enamored with Kenni that he could not stay away...while it endangered her it also managed to bring them closer together. Carter, however, was still about that life and eliminated every threat to them.

Listen these two could not keep their hands off each other and I loved that for them. Carter swore he wasn't romantic, but he had so many beautiful gestures that really expressed his love for Kenni that I just didn't agree. Her happiness was at the top of his list and he made sure his actions followed. Kenni was also very thoughtful with how she handled Carter. She made sure he got the closure he was ready to give up on by just choosing her.

Together they were borderline clingy, sexy, thoughtful, and loving. Good read!
Profile Image for Toya  Davis-Stokley.
2,566 reviews102 followers
April 14, 2024
This was the read that we have all been waiting for and did not disappoint. I believe at the end of 24/3 we all held our breath and hoped that by some chance Carter and McKenna would reunite. It seemed that we would be disappointed, as Carter was still standing firm on his decision to stay away. However, when his enemies put McKenna potentially in harm's way, all bets were off. Carter was coming for his woman.

I felt the intensity of Carter in the first read, but as we were able to dig deeper into his life, I understood why he was this way. He had a lot on his plate, and the items seemed to be growing exponentially. One thing he knew for sure, was that McKenna was his, and nothing would ever harm her. It was sweet witnessing both Carter and McKenna adapt as they navigated their budding relationship. McKenna learning to trust Carter, not ask so many questions, and to sometimes leave well enough alone. Carter adjusting to having someone to care for, worry about, and give him love and peace, while still going about his "tasks". 😂

Their love grew stronger as they both leaned on each other to make this unorthodox situation work for them. I loved how Carter fought "being soft" but couldn't help the feelings that McKenna gave him. He would do anything for her. That epilogue was everything! 🤩
Would love to learn more about Brooks. Hopefully he will get a story soon. 👍🏾👍🏾
Profile Image for 'The Book Queen'.
6,016 reviews112 followers
April 14, 2024
Carter is the man

I thought when we last saw Carter that was the last time McKenna would see him too. The hallelujah book gods decided to grant me and my man a favor. Carter was back with a vengeance to claim me, oh my goodnes, I guess he came for Kenni as well. But he wreaked havoc in the lives of those who deserved his wrath. And a man without a brain tested his gangsta with a hit on Mckenna. I won't spoil it for you, but you need to read this one. But, stay clear of Carter.
Profile Image for WellReadRuby.
539 reviews113 followers
April 22, 2024
Well this gave more than what I was expecting from 243! The suspense to finally have peace was a wild ride and we got the HEA we deserved! Lol Great read!
Profile Image for Tanisa.
87 reviews7 followers
April 20, 2024
Wow! If you must know I am currently sitting like Keith Lee because I am speechless. The amount of raw emotions I feel after reading this book has left me a little bewildered. 😩

If you saw my review for Twenty-Four Three then you know that I proclaimed that I needed justice for Carter and Kenni because I didn’t feel like they got the ending they deserved in that book. There was no gotdamn way she was going to end Twenty-Four Three with Carter continuing his life as an assassin and choosing to live his life without McKenna because of his profession and McKenna having to settle for Tevin’s basic ass. Well K.C. Mills delivered shortly after I made that review and protest, and let me just say .. she did not disappointment me. 😮‍💨🥹

This book, this book baby — is soo much more than just the continuation of Carter and Kenni getting to their happy ending. We watch Carter move throughout this book continuing to be an assassin while trying to protect Kenni because some very bad people found out about her. BUT we watch Carter figure out and understand what truly happened to his father and mother. What tugged at my heart was how the landscape of his father and mother’s relationship was like his and Kenni’s. When we learned what happened to mama Reed and who was responsible … I shed a tear because my girl didn’t fucking deserve that. 😡🕊️

Some of my favorite parts of this book:
— Kenni and all of her questions. She had the right to ask 159374 billion questions. YOU LEFT ME, SIR! 🤷🏽‍♀️😂
— Carter’s possessiveness of Kenni. Baby, if you thought the wrong thing about Kenni, he was busting your ass. 🔪
— Carter and Kenni’s thoughts throughout the book. They really added another layer. 💭
— The butterfly scene. 🦋
— The art auction. 🖼️
— What Kenni did in reference to Carter’s father and mother. She healed that man in ways she didn’t know she could. 😭
— Drea. I loved Kenni’s best friend. 💕
— Brooks. He grew on me. He isn’t an asshole anymore. 😝
— Chapter 13, 14, and 15 took me for a ride.
— All of the epilogue. 🥹👶🏽💜

I didn’t know what to expect for part 2, but honestly, K.C.’s exceptional writing skills exceeded my expectations. These chapters were 20+ minutes long didn’t bother me because I wanted the whole story and more! The way she connected everything and told the story in Loyal by Default was the perfect way to give Carter and Kenni their happily ever after. “My family. My balance.” ☺️
Profile Image for Jahda.
1,068 reviews317 followers
April 14, 2024
3.5 ⭐️ Despite only knowing each other for three days, I really wanted Carter and McKenna to be together when I first read the first book. It felt like a tease. As a result of Carter's lifelong adversaries, McKenna and Carter reconcile in this book. This was a calm and easy book to read. There is no doubt that Carter and McKenna want to be together, but they are still getting used to each other and their relationship.
Profile Image for Hloni Dlamini.
123 reviews6 followers
March 26, 2025
Carter Reed made being an assassin so sexy.... what a man
Profile Image for Jaleesa.
407 reviews60 followers
April 12, 2024
Carter and Kenni

I loved everything about this book. I’m so glad KC gave us more from these two. I found myself giggling and swooning way more than I expected. Who knew Carter would love like that? Whew. Anyway read it.
Profile Image for Tina.
960 reviews157 followers
April 22, 2024
4.5 🤗😍😅👰🏽🔪

Check Content Warnings

Trope: Black Love, second chance, close proximity, criminal activity, revenge

Enjoyment: 4.5 ⭐

Character development: 4 ⭐

Emotional: 2 ⭐

Sweet: 4 ⭐

Romance: 3.5 ⭐

Heat\steam: 4 ⭐

Intrigue: 4 ⭐

Action: 1 ⭐

Violence: 4 ⭐

Story\plot: 4 ⭐

World Building: 3.5⭐

Enjoy!!!

Profile Image for Roslyn Jones.
31 reviews3 followers
April 17, 2024
Yes!!!

I'm so glad KC gave us this couple back!! I love how she took an unconventional situation and navigated an awesome journey! Great job as always!! Hopefully, we will see them again!
Profile Image for Lauren Lane.
382 reviews2 followers
July 8, 2024
spoilers

I loved this book so much! Love that he couldn’t leave her alone. Even tho him not being able to, put a target on her back. He protected her and wasn’t letting up. At first I was waiting for Brooks to mess up. I thought for sure he was going to do something but I’m so glad he didn’t.
Anyway, great read as always by this author.
Profile Image for The Urban Fiction Librarian.
385 reviews46 followers
July 19, 2025
Didn’t know how Carter was going back to get Kennie but he went back and got my girl and became a new man. He loved, he shared, he opened up, and he became better. Kennie was everything Carter didn’t know he needed. He was everything Kennie needed plus more. To see the surprises, to learn about Carter’s parents to see how Cohen moved him Carter. Yes!!!! Loved it. And the relationship Carter started building at the end. This was the perfect ending
Profile Image for Keesha.
610 reviews20 followers
December 12, 2025
Chile Carter turned Kenni’s life upside down but not as much as Kenni turned Carter’s life upside down. Carter really don’t eff with anybody but Kenni. And he don’t play about her!!! Literally anybody will catch a bullet for thinking about messing with Kenni. McKenna if he’s mad at her. I didn’t see his family drama coming but I’m happy for their HEA.
Profile Image for Weekend Reader_.
1,090 reviews92 followers
May 26, 2024
💞

This entry came full circle but it was too easy. But there are more characters that were introduced so maybe the story isn't over.

CN: gun violence, torture, cheating, parental neglect, human trafficking
Profile Image for Izzy.
310 reviews10 followers
April 23, 2024
This was the PERFECT ending to Carter and McKenna’s story. My heart is so full and happy.
Profile Image for ReeBee.
28 reviews
April 14, 2024
Loyal by Default

After reading 24/3 I wanted more more more! Book 2 did not disappoint! I am satisfied. Thank you K.C. Mills for giving us more Carter and Kenni.❤️
Profile Image for Kyla.
163 reviews7 followers
May 24, 2024
⭐️⭐️⭐️.5
38 reviews
May 18, 2024
really a 2.5

It was slow. I struggled to finish. Ok storyline but drawn completely out to the point where I didn’t want to finish.
Profile Image for Plus Size Bibliophile.
1,205 reviews59 followers
October 8, 2024
Please add making love in a butterfly enclosure to my bucket list please and thank you.

Ya'll when I say this this was juicy, know that I am not over exaggerating. Carter came back for his woman, and he put it all on the line. Even tapped into his soft side and made some incredibly humble romantic gestures. I loved when he did soft stuff because it was soo over the top and he was so shy about it. It was too cute.

Anyways let's get into the plot. When we met Carter, he was an assassin who had been shot while on a job. He hooks up with our girl, they have an amazing connection however due to complications he has to walk away. I was heartbroken.

In this next installment, Carter learns that the complications can't be avoided so he does the only logical thing which is to go get his woman and protect her by any means necessary. This includes going from a solo operation to partnering with a new to me crime family.

I'm just now tackling the Crescent Falls books so I'm not sure if Kohen and his sons had been mentioned before but this was my first introduction to them, and it did not disappoint. I'm obsessed with this family and demand a trilogy for the sons and give my boy Brooks a story while we at it lol.

Seriously, I love seeing the interconnectedness of the different lives within CF be it the families that are part of the collective who have seats at the table, or college students who like to roller skate and have sweet love stories. I'm telling ya'll if you have not tapped into this world, you are missing out.

Back to my man Carter and Miss. McKenna. The theme of this couple was protecting one another. Carter wanted to protect her body and she wanted to protect his mind. Together they were the keeper of each other's hearts.

The reveal of Carter's past and his journey to confront the wrongs that had been done was top tier. The Angels of Death have my interested peeked and I'm finna need an omibus written on them. Please & Thank You.

Overall, I loved this couple. Carter brought so much emotion, intrigue, and depth into the Crescent Falls word and McKenna was likable and relatable. She was very human in her movements, concerns, and decisions.

Her mama pissed me off though. No spoilers but how you gonna be hung up on that doctor and give him all kinds of passes but treat my man some kind of way when he's willing to lay his life on the line for Kenni??? Make it make sense. Her dad is cool af though.

One last thing, for my Omari lovers we get to peek one of the brothers and their wife.

I highly recommend this read for anyone that likes suspenseful romance, lots of spice, stubborn protective men, and organized crime.



Profile Image for Tanira.
232 reviews
April 16, 2024
I think my expectations didn't match up well. After 24/3, I went into this expecting to see Kenna and Carter fall in love for real. I thought we'd get to see them in the real world, kind of like the relationships after Covid. In a sense, we did get this but it was more so Kenna throwing herself into Carter's world. Coincidentally, she just decided to take a month off work and didn't really interact with anyone except for a few phone calls. So, majority of the story revolved around Carter. In hindsight this is called the Legacy of Carter Reed, not the love story of Kenna and Carter so I should have known. I don't really know what the issue/resolution was (relationship wise) because Kenna just accepted whatever came with Carter. I get not requiring him to change but maybe inspiring him to be better. I didn't really vibe with Kenna too much. Sometimes I liked her but sometimes I strongly questioned her mental. Kenna was once an aspiring nurse so you would assume she'd have some level of care/morality for human lives. But nope. Point blank witnessed murder and I don't know if she shed a single tear. At the same time she put emphasis on earning her own money as a medical admin.. I mean I guess a goal is a goal is a goal. She knew this man for a few weeks and wanted to have his babies lol. Never mind her life being in danger and the potential danger that could come to her unborn/future child huh?

Overall, it was a decent read. I did enjoy the novella better but I'm glad we got a little closure here.
Profile Image for Kniah.
93 reviews
March 13, 2025
I almost DNF’d this because 6 days of reading is insane. I loved their story and the trajectory of their relationship but other than that the plot fell short for me. The more I continued I failed to understand why the book was as long as it was. Obviously Carter’s past was a reason to explain the length but with the way that was resolved was such a let down. Once he found out who was responsible for his parent’s death it all was wrapped up really easily. I think part of my problem is I wanted more action and more details. I wanted risk and for my nerves to be shot because he was playing with a dangerous group. The way his job was written and handled just wasn’t enough for my liking. Everything just seemed too laid back so I had no urge to keep reading because it was predictable. There wasn’t much of a thrill within the plot when it came to his job and his past and it’s sad because there could’ve been a lot of thrill. This books saving grace is the way the relationship was written. I loved seeing Carter’s “soft” side even though he refuses to accept he has one. Idk I really liked the book but man it either should’ve been shortened or made Carters job and past more difficult.
Profile Image for Tracy - loves to read .
1,015 reviews
July 3, 2024
Nothing like love, loyalty and protection

Carter - “It’s me and you, and we’re gonna ride this shit until the wheels fall off. When they do, I’m buying another set so we can do it all over again.”

Kenni - “I know you’re capable but that doesn’t mean you can’t depend on me. I may not have magic hands but I have logic when you’re irrational. I have calmness when you’re a raging storm. I’m the light to your dark. Protecting someone isn’t always physical, Carter. I can’t shoot a gun but I can cover your emotional wellbeing.”

The Assassin never imagined this
Like Mary J said:
I've never been touched like this-I've never been
I've never been kissed like this-I've never been
I never knew it felt like this-I never knew
I never knew a love like this

Carter found his love and he stopped at nothing to secure it, protect it, cultivate it and cherish it. Kenni embraced it, received it, demanded it and reciprocated it.

Awesome read!
Profile Image for Rise.
1,501 reviews
January 15, 2026
This was a slower-paced, character-driven story that really worked for me. The book takes its time laying the groundwork, letting the relationships, loyalty, and legacy fully settle before everything comes together, and that made the emotional payoff feel earned.

Carter and McKenna are clearly the heart of the story. Their relationship is shaped by history, responsibility, and unspoken expectations, which gives their connection real weight. I liked how much emphasis was placed on loyalty—not just as a concept, but as something lived and tested throughout the story.

I did find myself wishing Brooke had more page time, but it’s obvious it wasn’t meant to be his book. If anything, it just made me more excited for the possibility of him getting his story and finally finding love.

Overall, this was an easy 5 stars for me. It’s a strong, emotionally grounded read that left me invested in the world and genuinely excited to see what comes next.
8 reviews
April 23, 2024
The closure I didn't realized I needed!

After reading 24/3 I refused to believe that was it for Carter and Kenni! The way they connected and bonded in that short space of time, I just knew they would eventually find their way back to each other!

What I didn't expect is HOW that would happened. KC did her thing with this one!! The SUSPENSE, and the Twists that this story took, I truly enjoyed. I enjoyed getting to know Carter, learning about his past, only made me route for him even more! I loved how strong and determined Kenni was! She knew what she wanted from the beginning and was adamant
about NOT changing her mind! She was the perfect match for Carter! Dominant. Independent. Determine. Fearless. Everything Carter needed and more.

Thank You KC for filling this void!!! It was the perfect ending to this beautiful love story!
439 reviews5 followers
April 12, 2024
Carter Reed…a man after my own heart💕

Carter Reed was coming for my man Ezekiel Omari’s spot! Whew he was intense, captivating, and very dangerous. His only weakness—which wasn’t really one—was his love for Kenni. It was unwavering and he proved over and over again that she was his. Kenni was definitely the light to his darkness. Despite any reservations she may have had, Carter was it for her. It was so cute seeing him come to terms with his feelings. It was interesting to see Carter’s connections to other people. Even if he’d never admit it he loved Brooks, Kohen and his family, and even his uncle (well a little bit). I honestly would’ve liked more interactions with Brooks because his loyalty to Carter was unmatched. Oh well. I can’t wait to see what’s next.
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