What is it about the brother’s best friend and his little sister hooking up that is so irresistible? It's one of the most popular themes in romance, appearing over and over again.
Perhaps the main appeal is there's a sort of built-in chemistry that naturally exists between these two people who have denied what they want, sometimes for years. He wants to protect her like a brother. but feels something so much stronger and not very brotherly towards her. There are endless possibilities resulting from this chemistry. And whether it's a noble hero who's trying to keep the brothers' code of honor, or the heroine whose feelings of fondness toward her brother's best friend have grown into an abiding romantic love, the combination of these qualities and degree of urgency in giving in and crossing the line are what makes these stories our favorite.
In Samantha Young's On Dublin Street series, Adam and Ellie's story is a simmering, quiet tale told in the midst of Braden and Joss's big love, but it's not at all unexpected. In fact, we hope for their happy ending just as much. But between years of friendship and the fear of ruining that, along with worry about Braden's disapproval, misunderstanding and frustration have stood in the way. Though it takes a life-or-death crisis to finally bring these two together, Young throws the trope on its head when it's easy-going Braden who roots for Adam and Ellie most of all. They're one of those couples who we just know is meant to be because once they allow it, everything's easy, and two such sweet people deserve nothing less.
He chuckled, my diary still open in his hands. He asked, “So you wrote about me in all of these?” as his eyes scanned the pages.
Yes, yes I had. I’d had a big crush on Adam since I was ten and he was seventeen. That big crush had transformed into an even bigger crush when I was fourteen, and then just snowballed from there. I threw another diary from my childhood into the box and reached for the next one in the pile. “I’ve loved you for a long time, my friend,” I murmured.
— Until Fountain Bridge, Samantha Young
Then there's the best friend who not only considers the friendship he has with the brother, but also the massive amount of respect he has for his friend's sister. He knows what kind of woman she is, knows he isn't good enough, and this moral struggle is just as tempting. This is what holds Duke back, a former biker-gang member who's come back home to Destiny in Toni Blake's beloved series, where he wants to hide in the simple life. But his plans didn't include Anna, who's now all grown up. Above all, though, Duke is impulsive, and once they start, there's no stopping or going back.
And the truth was—he knew what he wanted to do. What he was itching to do.
The truth was—every time he’d seen her since they’d had sex on her couch and then again in her bed, it had been all he could do not to grab her and kiss her and hope it would happen again.
But he hadn’t. For all the reasons he’d just thought through. She was his best friend’s sister. He didn’t need this kind of complication in his life, especially right now. And even if she’d seemed totally into him when they were doing it – hell, she’d even started it—he still wasn’t sure what that meant, what she saw in him, or how she viewed him. And frankly, he still wasn’t sure he wanted to find out. He knew he was no good for her, not in any way that went beyond sex – surely she knew it, too.
—Half Moon Hill, Toni Blake
Alison Kent's Dalton Gang trilogy is one of the best-kept secrets in the erotic western genre, and Casper and Faith's story is a big reason why. They are fire and ice, love and hate, and made sure they stayed apart as they grew up by hurling insults at each other. That is, when Casper acknowledged Faith's existence, never mind her crush. Now Casper's returned to Crow Hill after years on the bull riding circuit, and she's rethinking playing it safe. But Casper still drives her crazy—in all the best ways—and with his reckless manner, they're no-holds-barred hot and heavy. Still, in the deep south, the brothers' code means something, and Boone will be none too happy when their affair comes to light.
“You, Faith Mitchell, have wounded me.”
“And you, Casper Jayne, are a scoundrel and you know it.”
He took a minute to respond, as if first running his life through the filter of her words. He looked confused and suddenly not quite sure of where they stood, or where to go next. “Is that why you wouldn’t have anything to do with me in high school?”
Now who was kidding whom? “You didn’t want anything to do with me. I got that message loud and clear.”
“Oh no, sugar.” His voice was deep, hungry, his gaze sharp and to the point. “The message you got was your brother’s.”
“Whatever,” she said because this conversation was one step away from precarious, and she could so easily fall.
“And anyway. You know the gang’s got a hands-off policy about sisters.”
That sounded as much like a coward’s way out as a challenge. She couldn’t stop herself. “You’ll climb on the back of a two-thousand-pound bull, but you won’t stand up to Boone?”
A vein throbbed in his temple. Heat rolled off his body to wrap her up, tangling her in his scent and the strength of his thighs. “You want me to stand up to Boone? Is that what you’re saying here, Faith? Because all I need is a sign and I’ll make it happen.”
— Unbreakable, Alison Kent
Kyle and Celia from Lorelei James's Blacktop Cowboys is that perfect example of two people bottling up every kind of feeling for way too long, romantic inclinations that left too long have turned into mutual irritation. So even though they've bickered for years, turns out that a drunken quicky wedding in Vegas is just what they needed to face what's there and come to terms with what they both want. And marriage is the perfect vehicle to explore everything without any excuses or examining it too hard. Suddenly they're all in for a life together—her brothers' protestations be damned—and all that they've long denied is now a relationship full of nuances, with sex as a very nice bonus.
“No.” Kyle loomed over her. “Not only no, but hell no. Fuck no. That is my stipulation. We will be man and wife in every sense of the word.”
“Meaning… we’ll be having sex?”
“Oh, yes, little wifey mine, we’ll be having sex. Lots and lots of sex. Sweet sex, raunchy sex, shower sex, sex on the floor, sex against the wall, sex in bed, sex in the truck, sex in the barn, sex on the tractor, and sex on this table.” He smacked it hard.
Her silver eyes went wide.
“And in case that wasn’t clear, I’ll say it plain. I like sex. A lot of sex. Morning, noon, and night.” He leaned closer. “It about killed me, laying next to you the last couple nights, not touching you. Not even able to hold you, my wife, in my arms. I want you, Celia, want you like fucking crazy. Make no mistake that I’ve waited for you for a long damn time and I’ve held off. But now that you’re legally mine and we’ll be playing house for the next six months? I won’t hold back. We will be intimate on the most basic level. As often as possible.”
—One Night Rodeo, Lorelei James
So whether they've grown up together and loved each other from afar for years, waiting for the right moment and sometimes not expecting it, with a protective hero holding the heroine on a pedestal, or it's a more sudden realization that his buddy's little sister is it for him, the brother's best friend and younger sister theme is everything great about romance. And the conflict of the brother's feelings, someone they both care about deeply, is a significant part of the equation, creating even bigger stakes and leading us to invest even more in the outcome that love must win out.
What are your favorite best friend/little sister books?
Tiffany Tyer is a writer and editor who loves reading and analyzing all things romance. She also works as a vocalist, a tutor, and a non-profit ministry assistant, and she loves it that way. Her book reviews can be found at Happy Endings Reviews, a blog she co-founded.