Title: Diamonds and Sparks

Rated: PG

Characters, Pairings: Jayne, Kaylee, River, and Simon. Mentions of the rest. Couples seen: Kaylee/Simon. Pre-one sided Jayne/River. Mentions of Wash/Zoe, with Mal/Inara hint, and past one sided Jayne/Inara and past one-sided Jayne/Kaylee. (boy that Jayne likes his crushes)

Timeline: After 'Objects in Space' and 'Serenity'. Though it is AU, there are some Serenity spoilers. Sort of a sequel to 'The Naming of Names', though you don't have to have read it to get this.

Summary: River keeps humming the wedding march, which is freaking Jayne out, so he goes to Kaylee to ask for advise on how to get the crazy girl to stop. 'Course that leads to a few surprising things.

A/N: Written for Angie, who said she wanted a Jayne and Kaylee friendship fic.

Jayne Cobb was not a man that would willingly seek advise out. And yet, there he stood, outside the engine room. Moving his weight from one foot to another, Jayne entertained the idea of just turning around and leaving. He could go back to his bunk and clean his guns, yeah that sounded like a hot Friday night.

"Hey Jayne." He nearly jumped. Kaylee walked right past the doorway and offered him a little wave.

"Uh, hey." It was then that he noticed that Kaylee had gone back to working around the engine room. She seemed to have forgotten he was there. That meant he could just go back to his bunk and-

"Did you need somethin'?" Jayne glanced over to see Kaylee staring at him. She was covered in grease and her hair was up in two very messy buns. It was then that he briefly remembered why had had such a crush on her when he had first come onto Serenity. Kaylee had a way of looking cute even when she was a mess. "Jayne?"

He blinked and shook his head, trying to clear it of past crushes. "Uh, I gotta ask you somethin'." Kaylee gave him a 'sure, go on' look. "It's 'bout the girl." Kaylee gave Jayne a knowing smile. "She keeps hummin' the damn weddin' march. Ever since Wash and Zoe named their kid. How do I make her stop?"

"She has?" Kaylee raised an eyebrow. "I haven't heard that. Though, Simon did tell me that she's been dancin' 'round the ship more. And she's been more peaceful since…since Mr. Universe's."

"You mean you really haven't been hearing her hum the weddin' march?" Jayne's brow became knitted in confusion. Why was the crazy girl just humming that damn song around him? It was creepy; gave him an uncomfortableness.

Kaylee shrugged. "No." A sly grin started to creep over her pretty face. "Maybe she'd tryin' to tell ya somethin'?"

Jayne made a face. "What, that she's still crazy?" He shook his head. "Nah, and 'less Mal is fixin' to ask 'Nara to jump the broom…" Jayne was cut off by a squeal from Kaylee. Jayne raised an eyebrow. "What?"

"Maybe Simon wants to get hitched! An' that's why she's not hummin' 'round me. 'Cause she's a dear heart and doesn't want to ruin the surprise." The look on Kaylee's face was pure joy and Jayne suddenly remembered why he had gotten over his crush on Kaylee and started thinking on her like a sister; girl was too damn cheerful. Jayne just couldn't be with someone who was always happy. Got damn annoying after a while.

Jayne just rolled his eyes. The thought of Simon Tam marrying Kaylee was not something Jayne wanted to think about. 'Cause if they got married, that meant they'd sex each other even more then they already did, and the idea of Simon having sex was about as creepy and unnatural as Simon's sister humming the wedding march all through the ship.

"So, why she doin' it 'round me for?" Jayne questioned with a small growl. "I don' like her and I don' like her bein' creepy 'round me."

Kaylee gave Jayne a 'could you be anymore clueless look'. "She likes you, Jayne. You're an easy mark to River. Teasin' ya is her new game. Simon says that River thinks you're funny." She let out a little laugh. "It scares Simon somethin' awful. He's scared River'll start working on a crush."

River thought he was funny? River could develop a crush on him? There was just something wrong with those things. River was not supposed to think he was funny; she was supposed to leave him alone. As for a crush, Jayne didn't want some crazy girl having feelings for him. 'Specially one that could kill him with her brain or shiny Reaver weapons. 'Specially one that came from the Core. Jayne had never done well with rich and fancy girls. It was why he had struck out with Inara when he had first come aboard Serenity. And he had carried such a torch for her too.

"Jayne?" Jayne blinked. He had forgotten he was talking to Kaylee. "Did ya hear me? I asked if ya had maybe seen Simon lookin' in jewelry stores when we're planet side." She looked at her, her eyes all hopeful.

Jayne raised an eyebrow. Since when did he hang around Simon when they were planet side? If Jayne was planet side, and if there was no work to be done, he was visiting whores. He most certainly didn't hang around the doctor. 'Cause when you hung around the doctor, it meant River wasn't far behind.

"No." Jayne answered simply. Kaylee's face fell slightly. Jayne hated when girls got all sad like that. "Bu' maybe I jus' ain't seen it."

Kaylee brightened again. So damn cheerful. "Yeah, cause Simon's hiding it. Last week when we was on Beaumonde and Simon took me and River to a show, he disappeared for a couple of hours. Maybe he…. oh, Jayne, do ya think he was getting a ring!"

"Aw, hell, Kaylee, I don' know." Jayne ran a hand through his hair. This was not something he wanted to talk about. He had come to the engine room to ask Kaylee how to get River to leave him alone, not talk about her and Simon and her getting hitched to Simon. "I jus' want to know how to get rid of River."

"Jayne, she likes you. You can't just make her stop. Just be happy she ain't tryin' to beat you no more." Kaylee gave him a little smile. "You're her friend now, why don't you like that?"

Because River made him comfortable. Had from day one. With her fragile looking body, and her big soulful eyes that always seemed to be looking into his soul, and her shy smiles, and her soft skin, and her intelligence that made her think the bible was funny and had once gotten her into so much trouble, and her purity, and her sweetness, and her graceful movements, and her crazy talk that almost made the 'verse have meaning and beauty. And-and when had he started thinking about River as more then trouble and an annoying little creature?

"Jayne!" Kaylee's voice broke through Jayne's thoughts. "You are somewhere else tonight."

"Sorry." Jayne muttered. "I…just got a lot to think on, is all. I never wanted her on the ship. Never wanted anything to do with her and suddenly she wants to be friends. It's all manner of confusing."

Kaylee gave him a pitiful look. "No, it ain't. Not everything you think is mean and River just sees that now. Just treat her like family, like a little sister, and it'll work out okay."

There was just one tiny problem: Jayne didn't think he could think of River as a little sister. He had once had a crush on Kaylee, but now she was like a little sister. He had once carried a torch for Inara, but now she was just the captain's almost woman. He had only ever seen River Tam as an annoying creature that was a threat to him. He honestly couldn't even being to think of her as a little sister. So, what could she be to him?

"I still don't like her." Jayne stated in an overly annoyed way, which meant that he did like her. Kaylee tried not to smile to widely, not wanting Jayne to know that she knew that he didn't actually hate River.

"River!" Kaylee smiled widely. "Hey!"

Jayne quickly turned around to see that River was standing just behind him, nearly hidden by his body. Jayne moved into the engine room and tried to stay away from River as she seemly floated into the room, her bare feet hardly touching the dirty floor.

River glanced around the room, her eyes taking everything in faster then Jayne thought a human could. But then again, River wasn't all that human anymore. She was a weapon, a machine, a reader. Jayne had to remember that, it keep things simpler. River gave Kaylee a shy smile.

"Somethin' up, sweetie?" Kaylee reached out her hand and River took it.

"Simon's nervous." River stated simply. "He's got his heart in a box and it's shiny. Everything in the box shines like stars on oceans. Little diamond sitting on silver."

Kaylee let out such a loud squeal, that Jayne thought the little mechanic sounded like a fire alarm. "Really? Oh River, this is so…so shiny!" She quickly wrapped the younger girl into a huge hug. "Isn't that shiny, Jayne?"

Jayne snorted. "I guess."

Kaylee rolled her eyes. "It is shiny." She turned her attention back to River. "He's goin' to ask me soon, right?"

River offered her best friend a smile. "Soon. He asked me first. Wanted permission. Wanted to be sure I wanted us to be legally connected. I do." River let Kaylee hug her again, before she want on. "I love you. I love Simon. Simon loves you. You love Simon."

From his corner, Jayne rolled his eyes. "Everyone's got love, then?"

Kaylee shot Jayne a look. "Jayne!" She returned River's smile. "I'm just….this is…"

"You always wanted a little sister." River supplied in her simple way. "I always wanted Simon to be able to talk to a girl."

Jayne had to laugh at that one. As River had once said, Simon was a boob when it came to girls. He had only gotten the courage to tell Kaylee that he loved her because he thought they were going to die.

Kaylee ignored Jayne. "Oh, Simon can more then talk to me now." She let a wicked smile creep across her lips. "I can't believe I'm goin' marry Simon. I'm goin' be Mrs. Dr. Simon Tam. I'm goin' be Kaylee Tam! No, Kaywinnet Lee Frye-Tam. No, Kaywinnet Lee Tam. No, Kaywinnet Tam."

"What you at this moment is annoying." Jayne muttered, more to himself then to the girls. Kaylee shot him a dirty look. "What?"

Both River and Kaylee rolled their eyes, but it was Kaylee that spoke: "River, that why you been hummin' the weddin' march 'round Jayne?"

River glanced over at Jayne. "It was a secret. Simon said I wasn't to tell. But, I have too many secrets to carry that aren't mine. This one wasn't bad. It wouldn't hurt Jayne to know. Serenity's a family; you can tell your family secrets." She looked at Kaylee and smiled happily. "Jayne's my friend, now. He doesn't hate me anymore. You can tell secrets to your friends too."

"Aw, that's just about the sweetest thing I've ever heard." Kaylee put a hand over her heart. "You and Jayne are friends."

Jayne would have respond with a forceful: "No we ain't!", but was stopped by River. She had suddenly gone very still. Her head snapped up and she quickly turned to look out the door.

"River?" There was concern in Kaylee's voice. "Honey?"

"Simon's coming." River whispered. She made a disgusted face "He's sweating. And he's nervous and carrying the heart in the box." River closed her eyes and slowly counted. "One, two, three, four, five, now."

Simon appeared in the hallway and spotted his sister in the doorway of the engine room. "River."

"Simon." River said. She glanced back at Kaylee and then spared Jayne a glance. "Kaylee and Jayne are here, too."

Simon nodded, hoping he wasn't blushing. It would be so embarrassing to blush during a marriage proposal. He moved his hands to his pants and tried to get the sweat off. "Oh? That's nice. Uh, River, could you and Jayne come out here for a moment? I need to speak to Kaylee in private." He gave his sister a smile, as if to tell her the Tam family was about to get a little bigger and she'd be getting an older sister.

River turned back to Kaylee and gave her a thumbs up before she breezed past Simon. Jayne took a moment before grunting and leaving the room.

Simon and Kaylee stood across from one another, somewhat awkwardly. This was perhaps one of the biggest events in their young lives and they were both nervous as all hell.

"Kaylee, we've been together for a few months now." Simon began slowly. "And River's very fond of you. And I-I love being with you. You're so beautiful and caring and cheerful. You're full of live and I love…I love you. And River approves of us and I asked Mal and he…he seems to be alright with the two of us. So," Simon swallowed and got down onto one knee. Kaylee held back from jumping around the engine room. "Kaylee, I was wondering if you would please do me the honor of becoming my wife." He took a box out of his pocket and opened it, reviling a tiny ring.

Kaylee let out yet another happy squeal of delight. "Yes. Yes, yes, yes!" She quickly pulled Simon to his feet and gave him a hug that was followed by a kiss. "Simon! We're getting married. I gotta wave my folks." She grabbed his hand and pulled him out of the engine room. "We gotta go wave my folks and tell 'Nara and Wash and Zoe and the cap'n. And we gotta wave Shepard Book at Haven and-" She whirled around to give Simon another kiss. "I love you. This is gotta be so perfect! We're getting hitched." She moved on, dragging a beaming Simon behind her.

Over in the sitting area, just outside the infirmary, River and Jayne sat together. The loud squeal, followed my Kaylee's rapid talking and the sound of Simon being dragged through the ship let the duo know that Simon had asked and Kaylee had said yes. Jayne stole a glance at River to see that she had a little smile on her face.

"Guess your brother and Kaylee are goin' jump the broom." Jayne thought out loud.

"Simon spoke and Kaylee went into a dream." River agreed. "Her mother will bake a strawberry cake."

Jayne nodded. "Sounds nice."

"Two weeks." River went on, ignoring Jayne. "She'll be able to call me mei-mei and mean it." River glanced over at Jayne. "I'll stop humming the march now. You won't have to be annoyed with me, anymore. Friends shouldn't stay annoyed with one another. It isn't right. Families shouldn't be annoyed with one another either."

"We ain't family." Jayne reminded her.

River gave him a look and rolled her eyes. "Our family doesn't share the same blood, but our family is a family just the same."

"You think of me as family?" Jayne didn't know exactly how to take that. He knew he didn't hate River anymore. Didn't think of her as a danger. Hell, he didn't even want to get her off the ship anymore. But, he also knew that he couldn't think of her as a little sister.

River shrugged. "We all play our parts. Brother and Father protect me from the monsters in my head. Mother and Aunt teach me, are strong for me. Sister plays with me, makes me smile. Grandfather and Uncle make me happy, make me laugh for no reason at all. Nephew is my hope. My Jayne is my Jayne; his role is undefined. Friend, though. Always a friend." She offered him one of her sweet and shy smiles before getting up. She started to go toward the cargo bay, but stopped half way there. River turned her upper body around to look closely at Jayne. She stared closely at him for a moment, before smiling widely and skipping off into the cargo bay.

Deep inside Jayne a torch suddenly sparked a new tiny light.

The End