Last Mistake

by Lauren Biel, Kayden Lukakis (Narrator), Helena Walters (Narrator)

Last Mistake is a LIGHT GRAY story with medium spice level and high angst! This story originated as a serial on Kindle Vella!

Harley hates me, and my past deed haunts us…Until opportunity strikes to make it right and, for the first time, the hatred she holds for me disappears. Now she’s falling for the man beneath the mask—me.

She needs to know the truth, but in stolen moments between whispered confessions, I chip away the walls around her heart in search of the woman I should never want... not like this.

But I crave her.

Time is ticking, and soon the masks will come off and the truth will be revealed. What happens when she realizes just how sordid this connection really is?

Last Mistake is a forbidden romance novella that is on the LIGHTER side for a Lauren Biel book. Please still check content warnings on LaurenBiel. com.

Genres: Dark Romance, Novella, Audiobook, Stalker, Romance, Dark, Halloween

3 pages, Audible Audio

Published December 15, 2025

About the author

Lauren’s stories are often emotionally raw, with lots of twists and turns. She describes her writing as “where light meets dark”, which represents how her witty humor compliments the darkness in every story. Instead of trying to mold her writing to fit in a box, she chooses to be unapologetically herself. While her focus is on Romance with dark elements, subgenre is no constraint for her. The common theme in every book is finding love when you least expect it. She enjoys putting her characters through tribulations, allowing their triumphs to be that much more poignant. Make sure you have your seatbelts secured. It’s always a bumpy ride.

When she’s not working, she’s writing. When she’s not writing, she’s spending time with her husband, her friends, or her pets. You might also find her on a horseback trail ride or sitting beside a waterfall in Upstate New York. She has a pretty normal life, yet her stories are anything but.

Reviews

[Celia {Semi Hiatus}]

•| ⊱✿⊰ |• 4,5 Stars •| ⊱✿⊰ |

Let me start by saying, I love Lauren Biel books, so my rate may be a bit suspicious...
Although, it's banned (I don't know why it's taboo stepbrothers with both different parents, but... This is only my opinion), this is so soft...
I was hoping for a darker story, hoping... The warnings were there, this won't be the kind of usual book Lauren use to write.



Mason and Harley are amazing together, and I loved both Mason and Guy.
It's funny to see how they interact.
I can not say much about this book without spoiling.

[Wobilba]

This was an okay read. Would have been better if the FMC wasn't very much annoying.

[RavenRose]

Protective step-brother with pierced 🍆 I love it! Great storyline, dark forbidden and secret relationship.

[Smutty Little Books]

Last Mistake was everything I expect from a Lauren Biel book.

Her stories are the ones you pick up when you’re craving something spicy, dark, and truly morally questionable and this one definitely delivered. Sometimes I just want a fast-paced, depraved read, and this absolutely hit the mark. While this one wasn’t as questionable as others she’s written, it still had its dark notes.

Keep in mind, these books like this aren’t for everyone. These books are for the dark and depraved readers so make sure you check triggers 🫶

[Mysti]

UPDATED with audio information.

I definitely did not do this book justice when I first reviewed it. It’s really freaking hot!! You’ll be super pissed at the FMC, but Mason makes everything worth it. Hot, forbidden, and sooooooo yummy.

“You’re my forbidden fruit, sweet girl.... I’m trying so hard not to take another bite of you.”

Mason (21, welder) found himself in trouble at 17, and even though he was innocent, his stepsister refused to believe him. When an enemy from the past threatens her, he makes it his mission to protect her, even if he has to hide his identity to do it.

She was mine whether I was Guy or Mason. Whether she was my stepsister or not. Mine.

Harley (19, virgin, twat) does not want her estranged stepbrother staying at her house. Not only does she hate him, but she’s just started hooking up with a masked man she met at a college party, and he’d only get in her way.

Before the incident, she disliked me. After the incident, she hated me. By then, there was no breaking through the walls she’d built around herself with the bricks I’d handed her.

Several nights of masked snuggles turn into raging desires. Eventually the clothes come off, and they burn up the sheets!

I had made a lot of mistakes in my life, but I wanted her to be the last. My last mistake.

The enemy makes a move, the truth comes out, and an HFN.

“I love you, sweet girl. I shouldn’t, but I do. I never thought I was capable of loving another person, but you live in my mind all the time, Hal. All the time…. and if that isn’t love, I don’t know what is.”

SEX: Very delicious!! The V is taken at 49%. No condoms are used, but he pulls out before the climax. Once she gets on BC, he stops using a condom. The sex to story ratio was really good.

MASON: I love him and his pierced dick.

HARLEY: On one hand, I freaking hate her for being so cruel to him. On the other hand, I understand how her age and immaturity led her to believe the things she did.

AUDIO: It’s a duet, but I think reading it was better. Kayden Lukakis and Helena Walters are both just OK for me. I def wouldn’t pay for the audio.

[Kimberly]

As always, this book was a fucking masterpiece and Lauren can do no wrong 🙄 It’s sickening how ridiculously obsessed I am with her writing 🫠🙈😂😂
I literally have no words!!! 🤌🏻👏🏻👏🏻

[Spade Sixx]

I Squealed

🌟: 4.5/5
🌶️: 4/5

This was a refreshingly sexy read! Don’t get me wrong, I do loooove Lauren’s traumances, but this was a wonderful pick me up! The forbidden trysts, the “touch her and d*e” trope—it’s all too good to pass up. Loved this little novella!

[Jessica]

Short, spicy, and a little sweet. The mask idea is enticing. Enjoyed. 4 stars ⭐️⭐️⭐️⭐️

[Jess]

Quick hot novella featuring step-siblings and a masked man … and he calls her “sweet girl” 🫠

[Jennifer]

I have a feeling this will be the lightest thing ill read all day 😬

[Jennifer Porter]

Devoured this in a few hours 😍

Lauren is right, this is waaay tamer than her usual stories, but it was still HOT 🔥🔥🔥🔥

Quick read, tons of spice, and such a very naughty fling turns into what should be forbidden 😈. As always fellow readers, make sure to read any and all trigger warnings!

I'd love another story with these 2. For being step-siblings, Lauren still made their chemistry fly off the page as the story went on.

Thank you for the chance to read this 💜

[FeFe]

1st person/dual pov
Spice: 4/5

Such a cute and spicy novella to read during spooky season! Not as dark as some of Lauren’s other books but the dirty talk and the steam are still on point. The story itself was really entertaining and I was a big fan of the way we get to see both sides of Mason’s character due to the circumstances. Spoiler Alert - I friggin loved both of his sides because let’s face it he was written by Lauren! 🤣🤷🏻‍♀️

As always check the TW before reading just to be safe! 🖤

[Lexi Rivera]

I'm a sucker for a good taboo book, and then the fact it's a lauren biel book!? Say less. Immediate five stars.

[Neapolitan670 📚🖤]

Another quick read from Lauren. A forbidden romance or is it? I suppose it depends upon your point of view, it could be classed as taboo, they are step-siblings but they’re not blood relations 🤷🏻‍♀️

Masons’ past catches up with him but fortunately he’s there to protect Harley before the worst can happen or did it already?

I was excited to have won this ebook from Lauren as it was in my TBR anyway, so this prompted me to read it. Totally enjoyed the story, who doesn’t enjoy a masked man? Plus the story giving us Mason’s real past history 🖤

[mads]

3.5/5 ⭐️

short, smutty, and taboo in true lauren fashion

[Heather Saizar]

I love Lauren Biel and her novellas are always a good time! This one was a quick read, step-siblings romance with masked men thrown in so if you need another book for your monthly goal this one’s it!

[Nicole Greene]

Loved this step-sibling novella! This wasn't as dark as Lauren's other books so if you want to start with any of her stories, try this one.

The story sucked me in from the first page. The MC did minor time in juvie and Harley never wanted to hear his side of the story and just assumed the worst. But regardless of her constantly pushing him away he is still protecting her without her knowing it. Harley at times was annoying but that was because she was naive and stubborn for no reason.

Loved the tension build up in this story and I would recommend this if you love spicy taboo romances❤️🌶️

⚠️Check the TW before reading just to be safe⚠️

[Tea&Biscuits]

A spicy step sibling taboo romance. On top of that, a stalky masked man. Yes, please! Now, this novella isn’t anywhere near as trauma inducing as Biel’s usual work but you won’t find me complaining. I actually rather enjoyed the rate of the plot progression. Sometimes I feel like I miss character development with novellas but that wasn’t the case with Last Mistake. I would definitely recommend this as an entry level read if you are wanting to start checking out what Lauren Biel has to offer.

[Nikki reads]

This book was just what I needed! Dark, delicious and forbidden! No one ever grips me like Lauren does! You’ll find her usual triggers in this book, I absolutely love Mason and felt so bad for him throughout the book. The perfect ending but I definitely need more of this couple.

[Alyx Reese]

Taboo and Steamy

Mason and Harley are step siblings who hate each other, right up until they realize that they’re each not who they thought they were.

Such a good book, great character, the tension between them makes for some spicy scenes. You’re going to love it!

[Sara Husser]

💜🎭I had made a lot of mistakes in my life, but I wanted her to be the last. My last mistake🎃🖤

"I was misguided, not a monster, but it was hard to change the mind of someone who saw you in their nightmares."

"After the incident, she hated me. By then, there was no breaking through the walls she'd built around herself with the bricks I'd handed her."

"Why did I feel the need to give her everything she wanted and more? Especially after how she thought of me. How little she thought of who I was. Who I am. Why did I think she deserved more when she thought I deserved so little."

"That wasn't darkness, Harley. That was just the tunnel before. True darkness doesn't come until I'm inside you."

"With her covered in my come, I realized what she was. She was f****** mine. Stepsiblings or not, I would devour her until I had my fill."

"Having her love me felt worse than when she hated me. At least when she hated me, I didn't know what her moans sounded like."

"You're my forbidden fruit, sweet girl. I'm trying so hard not to take another bite of you."

"I had made a lot of mistakes in my life, but I wanted her to be the last. My last mistake."

Every book I've read by this author has been amazing. I love how this author writes various shades of dark romance. This one was on the lighter scale, but it was super delicious and spicy 🔥🔥🔥. This is a shorter novella, but it packs a punch. I love that we get a stepsibling and hidden identity troupe in this story. If you love a masked man and Halloween, then this one is for you.

This story follows stepsiblings Harley and Mason. These two have always bickered and fought. Mason bullied her as he was frustrated with his mom re marrying. Harley hates him as he has an assault charge against him, but she doesn't know the full story. We see Mason watching over her as Jeff, the rapist, is out on bail and after her. She goes to parties where Mason shows up in a purge mask pretending to be Guy. They get close and it gets spicy. Mason feels horrible for lying, but he can only get her affection as Guy. She comes close to being assaulted a few times, but Guy saves her. Mason and her start to understand each other more, but then she finds out who masked Guy really is. Is it too late for Mason? Can he make her see that he's really not the monster she thinks he is?

These two were hot together. I loved their animosity and bickering they had going on. My heart hurt for Mason. He just wanted her to see that he's not that disgusting monster she thinks he is. The chemistry between these two was 🔥🔥. The spicy scenes were heated 🥵🥵. I loved how protective he was of her. I loved seeing their connection grow without his mask. He even brought her angry kitty to her 🐱😅. The ending was the best when they were sneaking around their parents 😏😉😈. I highly recommend anything by this author. 🖤💜🎭🎃🐱😈

[book lover]

•Step-Siblings
•Pierced Peen
•Secret Relationship
•Hidden Identity
•Masked Man
•Virgin FMC
•Forbidden Romance
•Taboo
•Stalking


This was everything I hoped it would be and more. Omg so deliciously spicy ugh. My only complaint is I wished it were longer 😂 I could’ve easily read a 300 page book about Mason and Harley.

Mason is trying to protect his step-sister from a bad guy from Masons past. In the process she becomes attracted to the masked stranger who keeps finding her at parties. They exchange phone numbers (his is one from a texting app) and grow closer the longer they text.

The way Harley finds out the masked man is actually her step-brother Mason sent me into orbit 😂 I had to put my kindle down because omg of course that’s how she found out. Shew the spicy scene they have in his childhood bedroom after having dinner with their parents was *chefs kiss*. I can’t believe this book isn’t talked about more.

If you’re looking for a step-bro masked stalker who hides his identity from his step-sister while doing spicy things to her, definitely read this! This book is banned so go to LB’s Etsy to get it💕

[Laci]

Last Mistake by Lauren Biel was a one sitting read for me. I devoured it in an hour.

Harley hates her stepbrother. Like, truly despises him. She sees Mason as one of the most vile, disgusting humans on the planet and wants absolutely nothing to do with him. Mason, on the other hand, is the painfully overprotected stepbrother who’s always watching from the sidelines, especially when it comes to keeping Harley safe. And then there’s the mask…and once those lines are crossed, everything changes.

The tension in this book is intense. The push and pull, the hatred mixed with something much darker, and the way everything slowly unravels kept me glued to the pages. Lauren Biel does what she always does best—dives headfirst into morally gray territory and makes it impossible to look away.

This story is a little dark (more so grey), twisted, and absolutely not for everyone, but if you know Lauren Biel’s work, you already know what you’re signing up for. She never disappoints, and Last Mistake was no exception.

[Drasevia]

Our goddes Lauren is simply a guarantee of perfect reading experience.🙇‍♀️ She managed to fit a crime, coping with trauma, truly disgusting revenge, mysterious masked protector, forbidden love, exquisite spicy scenes and even piercing in 🍆💦, in one hundred and twenty pages!
WHAT A RIDE!! 10/10.

[AshleyReadsSmut]

Def not a fan of the narrator casting :/ and the story was meh.


𝗢𝗩𝗘𝗥𝗔𝗟𝗟: ⭐️⭐️
𝗧𝗬𝗣𝗘: Novella
𝗦𝗘𝗥𝗜𝗘𝗦: n/a
𝗔𝗨𝗗𝗜𝗢𝗕𝗢𝗢𝗞: Duet narration

𝗣𝗔𝗜𝗥𝗜𝗡𝗚: M/F
𝗛𝗘𝗔/𝗛𝗙𝗡: 💖
𝗟𝗚𝗕𝗧 𝗥𝗘𝗣: 🚫
𝗪𝗛𝗬-𝗖𝗛𝗢𝗢𝗦𝗘: 🚫
𝗠𝗔𝗜𝗡 𝗖𝗛𝗔𝗥𝗔𝗖𝗧𝗘𝗥𝗦: Mason + Harley

𝗛𝗜𝗚𝗛𝗟𝗜𝗚𝗛𝗧𝗦:
♥︎ step siblings
♥︎ masked men
♥︎ stalking

[Adrianna Thompson]

Spotify really said “suggested for YOU” with this one. I’m SWEATING.

I’ve always been a little scared of Lauren Biel just because I know it can lean really dark, but this was at best light grey romance. Heavier on the taboo. The dirty talk? Immaculate. 🤌🏻🤌🏻

[eli]

Cute

[Nootka Lenoir]

Taboo, spicy, medium dark and a masked man.

YESSS PLEASEEEEE

[Kathleen]

Good “your mine” and protective smutty book.

[Tina]

I ended up rushing through the end of the book. I might be in a reading slump and this just didn’t do it for me.