Title: Little Sisters Can Be Wise Too

Summary: Mary Ann visits her brother in Hawaii to realize the McGarrett house has turned into a home.

Disclaimer: I own nothing.

Author's Note: This was written for the amazing Tiana-P as a birthday present, but I thought I'd share it with you all as an end of the year holiday gift! It was inspired by Mary's visit this season and how much I love the McGarrett sibling relationship, and how much I love McKono too, obviously. There will be three parts. Please comment if you take the time to read, it's just the nice thing to do.

* Also, this story fits into the Steve/Kono universe in my head which goes AU before the s2 finale, meaning Malia remains alive and Doris remains dead. My head canon has Steve and Kono getting together a couple years down the line so technically this is "future" fic as to where I see the characters in the happy, little universe I escape to. It's fun here, I'll let you visit through my fics if you'd like.

(If you're still reading this, hiiii! Most people seem to skip over silly little things like the author's notes, but a few of you awesome reviewers don't, so thank you for reading and enjoy the piece!)

Steve couldn't sleep like this.

And he'd slept in war zones. Bombs going off, soldiers talking while on watch, the static of walkie-talkies and radios constantly humming, the panic of danger a mere second away actual war zones.

He'd also allowed Danny in the house as a roommate. Danny, who thought the sound of the ocean was considered torture and put on infomercials to get a good night's rest.

This is worse than both those times. Combined. And multiplied by fifteen.

Maybe because of the constant giggling. What are they laughing about this time? What could possibly be so funny at one o'clock in the morning on a Tuesday?

He throws his pillow aside and marches out of bed, down the hall to the bedroom that's usually vacant, but is currently occupied. He pushes open the door, startling the blonde and the brunette on the bed as they jump at the noise and peek at him from behind the glowing laptop screen.

"What are you guys watching?" he demands.

"Porn," Mary Ann answers.

"YouTube videos," Kono says at the same time, giving Mary a jab with her elbow. "She's lying."

"And you should knock, you know," Mary Ann reminds him haughtily. "I have a right to privacy when I'm visiting."

Steve ignores her. "Do you have any idea what time it is?"

Kono bites her bottom lip as she looks at him in apology. "Sorry. Did we wake you?" She turns to Mary Ann to explain. "It's a McGarret house rule. No TV after midnight."

"Good thing we're on a computer then," Mary Ann clarifies to her brother dramatically.

"Don't you have work tomorrow?" Steve asks Kono pointedly.

"Yes. And I will be on time and not hungover," she promises.

"You've been drinking too?" he asks in surprise. "It's Tuesday!"

Kono and Mary Ann exchange glances of confusion.

"I don't understand what he's trying to say," Mary Ann says to Kono, who only chuckles.

"Just keep it down in here. Some of us have a task force to run. And if you're late tomorrow," Steve directs this part to Kono, "I'm gonna make you type up all my paperwork from last month's cases."

"Is that some kind of kinky foreplay for you two?" Mary Ann asks looking from her brother to his girlfriend, then back again for an explanation.

"No," Kono laughs. "He's just a slow typer."

Steve closes the door on them before he can argue that it's not his fault the keys are so small and his fingers are so big and masculine. Kono doesn't buy that.

The laughter starts again before he makes it back to his bedroom.

"And then this girl used to totally stalk him in the halls and at the gym, and where was that place you used to work during high school, Steve?"

"This story really isn't as funny as you think it is, Mary," Steve tells her with a frown.

"Yes, it is," she tells him and snaps her fingers at him, waiting for an answer on demand. "Where did you work during high school again?"

"That car garage near the mall," he answers.

"So, that's how you got so good with cars," Kono says as she smiles at him from across the dinner table and Steve nods.

"Right! The auto repair shop! Totally forgot. So, she'd stalk him there, and then the owner said Steve had to tell her to stop parking across the street cause no one could see the garage sign from the road," Mary elaborates with a grin.

Kono laughs. "Then what happened?"

"I don't remember actually. What happened next?" Mary Ann says, turning to her brother to finish the story.

"Nothing," he says with an embarrassed shrug.

"Oh! I remember! You fumbled a pass in the football game and she dropped you to stalk some other guy. Sorry," Mary apologizes with a wince. "I forgot about that."

"I bet you did," Steve grumbles with a glare.

"Aw, it's okay." Kono hides her smile and gives him a kiss on the cheek as she gets up to put her empty plate in the sink. "I like your first stalker story. I remember mine. Some guy would show up to all my surf competitions around the East Coast and bring me flowers after I'd won. He had this scrapbook of me. I wonder whatever happened to him," Kono muses out loud.

"That's creepy," Steve says, shaking his head at her story as he joins her at the sink. "Mine was nowhere near that creepy."

"It does sound creepy, now that I think about it," Kono admits with a laugh. "But I was young. I thought it was sweet back then."

"So, what happened? Did you go out with him?" Mary asks from the table, watching the two of them begin to do the dishes; Kono washing, Steve drying, their hands working in unison without missing a beat.

"Nah, I was with Ben at the time," Kono says, and Steve tries not to visibly cringe at the name. "But I always thanked him before keeping the flowers."

"Ah, Ben. Hottie from your surf days. Was he like your first love or something?" Mary Ann asks curiously.

"Yeah, I guess he was," Kono says with a shrug.

"Like, your first first love?" Mary questions again.

Kono glances at Steve from the corner of her eye before answering the other woman's question. "He was a lot of firsts, if you know what I mean," Kono adds over her shoulder to Mary Ann with a telling look.

"Oh. Gotcha," is all Mary says with a knowing nod.

It takes Steve a minute to get it but when he does, he cringes at the information revealed and a flash of possessiveness runs through his veins at the same time. It has been years since that relationship, but he doesn't want to think of Kono with anyone else; he wants is to think of her as she is with him - right now, right here, night and day. He wants to think of her as only his.

"I did not need to know that," he says with a grimace, tossing aside the dishtowel.

Mary Ann looks at him in surprise. "Did not think you'd catch that. Guess having a girlfriend has made you better at girl talk."

Kono turns to him apologetically, her wet hand grabbing at the sleeve of his shirt as he moves away from the sink. "Sorry."

"Mary, take over," Steve orders. "I wanna watch the game."

Kono finds him on the couch ten minutes later and slides next to him, resting her chin on his shoulder until he has no choice but to look away from the TV screen and face her.

"What?" he grumbles.

"Sorry," she says softly. "I didn't mean to make you uncomfortable by answering her questions."

"I'm not uncomfortable," Steve says, shifting uncomfortably in his seat.

"Right. Of course not. Cause you have nothing to be threatened by-"

"I'm not threatened," he interrupts quickly, biting back his anger and forcing himself to remain calm, reminding himself that there's no potential attack and the perimeter is clear.

"Good. You shouldn't be," she says, her hands coming to rest on his broad shoulders. "Cause the first time was completely awkward and horrible."

"Seriously, Kono?" Steve scowls at her words, clearly not amused by her deciding to share the details. "I don't wanna hear this."

"I mean, I was terrified and we were fumbling all over the place, and I don't even think he knew where to put what, and-"

"Kono, shut up," he says with a half-laugh as he kisses her, his lips firm as he tries to end the conversation.

She giggles as she quickly straddles him in one smooth move, her hands wrapping comfortably around his neck, her mouth pressing quick kisses against his in between her words. "And it was painful. Like, bad painful, not good sex painful, so that should make you feel a lot better-"

"I said shut up," Steve repeats as he places kisses down her neckline, stopping to tease the skin of her clavicle lightly with his teeth. She moans as she grabs at his shirt tightly, and he grins in success at the noise. His hands slide under her shirt, rough fingertips brushing the skin of her bare stomach and she shivers as she leans further into him, their hips aligning as if by some power outside their control. He releases a low groan as her hands slide down his chest, fingers dancing toward the waistband of his jeans, kissing him more passionately as she sighs dreamily against his mouth.

"Oh, god, ew!"

Kono breaks the kiss so fast at the interruption that he blinks in confusion. She wipes her mouth with the back of her hand as if that'll make the taste of him, the hunger for him, disappear. But it doesn't work because she's still breathing fast, her lips swollen from the kissing, her eyes cloudy with arousal.

"What the hell, Mary?" Steve says with a groan, his hands keeping Kono in place on top of him to hide his physical reaction to their impromptu make out session. He takes deep breaths and tries to breathe away the sudden lust he'd been overcome in. With Kono, it happens quickly and it happens often.

"You? I'm the one who's scarred here," Mary Ann announces dramatically, shuddering at the sight of them. "That's gross. People sit on that couch."

"Can we help you with something?" he asks politely, now that she's effectively ruined the mood.

"Right. Kono, I found that dress I told you about," Mary says to the other woman, nodding her head back toward the stairs. "Come try it on."

"Why do you need to try on each other's clothes?" Steve asks in confusion, the disappointment clear on his face as Kono extricates herself from his lap, giving him a quick kiss as she pulls away. "You're like a foot shorter than her."

"So? I wanna see how she looks in it, duh," Mary explains sarcastically with an eyeroll.

Steve watches them go upstairs together and is left only with the television for company. He can hear them laughing again.

"When I said I wanted a ride home from the mall, I didn't mean I wanted to waste my time at the grocery store on the way," Mary complains.

"Well, you're staying with us until the weekend, and we need food. Kono's still at work so you're stuck with me," Steve tells her as he paces the aisles and grabs whatever labels look familiar from their now nearly empty refrigerator and pantry shelves.

"Okay, I do not eat that much. It's your girlfriend you should blame for your high grocery bills, not me. Where does she even put everything? She may be tall, but she's tiny."

"I have no idea," Steve answers honestly, because it's been almost a year now and he still hasn't figured it out. And he's the leader of Five-0. Talk about a real mystery.

"And why are you getting vegetables? She can't cook."

"But I can," Steve reminds her.

"So that's why she keeps you around," Mary concludes. "I knew it had to be something like that."

"Cute," Steve comments as he navigates them down the freezer aisle. "Grab one of those eclair boxes," he orders.

"'Three times the chocolate, only twice the calories,'" Mary reads from the label and looks at her brother with a chuckle. "Is this your new comfort food or something? Cause I am totally gonna send a picture of this to the Navy for your permanent record."

"Not me," Steve scoffs. "Kono loves them. And grab those colored popsicles for Grace when she visits. And..." He hands her a carton of strawberry banana ice cream from the freezer. "You always loved this flavor, right?"

Mary smiles at him radiantly as she takes the carton. "Yeah. Thanks."

Steve smiles back, clearing his throat against the emotion that overwhelms him and the urge to hug his baby sister in the middle of the frozen desserts aisle. He gets a hold of himself and pushes the cart towards the checkout counter. "Finish it before you go cause as far as I remember, that stuff tastes like crap."

"Hey! Don't insult strawberry banana!"