AN: I own nothing. This was originally a one-shot about a training session, and I thought 'what if I expand it?' The entire story takes place in one morning with flashbacks/memories to past training sessions and experiences.

A more accurate summary might be: ~10 chapters about two people falling in love. (Truly, this is 90% focused on Callen and Nell's interaction. If that doesn't interest you, turn back now.)

Again, I want to thank everyone who read/left feedback on my last story. It is directly because of you all that I was motivated to finish this story, and what this has turned into.

Warning: Brief mentions of past child abuse, nothing graphic, or worse than what we've seen in the show with references to Callen's past.

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"Try and look more miserable," Granger suggests, as everyone reluctantly finds spots on the mats in the gym. They've lined up in a predictable pattern, anticipating how they want to pair off: Deeks and Kensi, Sam and Eric, Callen and – oh hell no.

He shakes his head and points two fingers at them, indicating they should separate.

"Problem?" Callen asks, feigning confusion. He stands slightly behind Nell, and to the untrained eye, he appears casually indifferent. Granger (and perhaps the rest of the room) know better.

"Yeah, the two of you together are like fire and gasoline, I'm not dealing with that today."

Callen glances at Nell who shrugs, as if she, too, has no idea what Granger means (quite laughable, considering the circumstances). "Guess he can't handle us," Callen says.

"I wonder why?" Nell asks, linking her arm with Callen's, the picture of innocence. "We treat each other so fairly. I think we're NCIS's golden example when it comes to sparring, aren't we?"

Callen thinks about that for a moment too long. "I don't know if 'golden' is the word you're looking for."

She smiles up at him. "It's the word I'd use."

Her words would have more impact if she and Callen weren't regular sparring partners with an equally long record of not playing fair. It had started about seven months earlier, when Nell asked around for someone willing to help her train in their off hours. Callen had the most free time, having not much of a personal life (or none at all, as Nell liked to say) and so he'd agreed. Truth be told, once the idea of helping her learn to protect herself had gotten into his head, he couldn't shake it. She got into trouble far more than she should, so honing her fighting skills was a cause he willingly threw himself into.

It only took one session for him to see her potential. She was good (NCIS ensured they were trained well) she just needed more practice to become great, and since it wasn't a skill she was prized upon having, she didn't have much time within the bounds of her actual job to practice – which led to early morning sessions and late night sessions, and, increasingly, weekends where they'd meet up to practice. They got together a few times a week, depending on their cases, and their moods. Lately they practiced more than they did in the beginning.

She excelled to the point that, outside of Sam, no one could anticipate him more than she could. He took no small amount of pride in her success either (which he loved to goad her about – every win she got was thanks to the techniques he'd taught her, and every loss was due to her poor application of those techniques – this usually led to her laying him out on the mat, but he didn't mind).

Granger (mostly) liked that they had started training together. Callen made Nell stronger, and in turn, Nell made him…lighter somehow. Granger couldn't exactly describe it, except to say that Callen smiled easier, laughed more, and generally appeared as if he weren't carrying the world on his shoulders. He'd often catch the younger man glancing at the time impatiently, as if he had somewhere to be, when everyone knew his only plans were to train with Nell.

They both seemed to have become better at their jobs because of their training, so Granger hoped they'd keep up the positive influence on each other. Truthfully, in the long run, he hoped their newfound acquaintance would translate to Callen (and by extension, Sam) throttling back on the intensity with which they approached certain cases, especially those that they found to be of personal significance.

The only potential problem was that Callen had decided to teach Nell what he called 'real life scenarios'. Fights outside the safety of training sessions were messy and bloody and no one fought fair – and as Callen constantly reminded Nell: you could die. Granger couldn't begrudge Callen wanting to teach Nell how to save her own life, the issue was that it meant regular training sessions were hard for both of them, having to readjust to the rules of fairness set forth by NCIS for those encounters.

Granger had talked to Callen about it, warned him about teaching Nell the proper way to fight according to the rules. Callen had agreed, and they practiced training with rules and without. However, they both preferred training 'without' and it was generally their default mode. Callen dedicated himself to teaching her every trick in his arsenal, and she picked up on them faster than anyone expected.

As a result, in any kind of training situation, they were the two worst people to face each other in terms of surprise maneuvers and unfair hits. Nell still felt a compulsion to follow the rules when it was required, and she at least tried to get Callen to comply. Whether he listened or not was up to Callen's mood that day, and if he disregarded the rules, she pretty much had to, as well, to keep up with him. In the end, it was easier for Granger to separate them and save himself the headache.

That reminded him – he needed to stock up on aspirin, because they increasingly took their 'training' outside of the gym. More than once, Granger had seen them try to surprise each other during a normal day at work. Hetty had put a screeching halt to that, at least in Ops, when Callen had surprised Nell one day and her automatic reaction had been to lash out and shove him into Eric's monitor, which went careening to the floor (Callen swore Eric had almost cried).

Granger still wasn't convinced they'd completely stopped when Hetty was conveniently absent – he'd walked in on more than a few suspicious encounters, and if it were literally any other two people in the building, he'd have wondered exactly what was going on. Somehow, though, he knew it was just their strange way of training. Their relationship confused him more than anything else. He did what he liked to do best with problems he'd rather not examine too closely – he ignored it.

In any event, it's an old argument they've rehashed many times. Granger doesn't want to deal with their antics and they damn well know it, which is probably why they've tried to pair up today. If giving each other grief is their number one joy, then giving him grief probably sits squarely at second on each of their lists.

They both watch him, trying to determine how serious he is. They decide not to test him – there's always later in the morning.

Callen pushes her toward Eric. "Get away from me before Granger has a meltdown."

Granger uses every fiber of his being to avoid rolling his eyes – he has to set a professional example. "I'm not going to have a 'meltdown', I only want this to be a fair fight." He suppresses a sigh when Callen and Nell only smirk at each other. "I know I don't have to remind you that you two are incapable of such a thing."

"You make us sound so…formidable," Nell tells Granger, sounding quite flattered. She moves over to Eric's side anyways.

"No. No, no, no," Eric begs. "Make her partner with Kensi. Or Sam. This isn't fair to me."

Nell stops herself from making a joke about accidentally maiming him. "I'm not going to hurt you," she promises.

"That's what you always say to Callen. Right before you try to hurt him."

"He deserves it," Nell says smoothly, ignoring Callen laughing in the background. "Besides, the difference is I mean it this time."

Granger feels for Eric, he really does, but he knows the analyst has a better chance at learning with Nell than with Sam or Callen. "Let her teach you. I don't think Nell's out to hurt you, Beale."

Eric isn't so sure. He takes a deep breath when Nell smiles at him – he isn't reassured; he's seen the things she's done – not just to Callen, but to Sam, Deeks, and Kensi when she occasionally switches up her sparring partners.

"You look like you're lining up for a firing squad," Granger scolds everyone, when he notices that no one looks particularly thrilled to be at their mandated session.

Deeks raises his hand. "To be fair –"

"Shut up, Mr. Deeks. This will be less painful than an execution…for some of you. As you know, NCIS's main priority is the safety of the public, its agents, and yes, even the criminals we pursue. We've recently updated our training manuals based on analyses of the past year's cases, agent feedback, and new research into the most effective training methods. These guidelines reflect our continual aim of finding safer, more practical, less dangerous –" he directs this at Sam and Callen, "– ways of taking down suspects."

Callen doesn't know how many times he has to explain last week to Granger's satisfaction. "I can't help it that McMillan chose to jump off that roof."

"After you broke his leg," Granger reminds him.

"A casualty of running away from me after he'd shot someone. Besides, he could have broken his leg in the fall. Prove that he didn't."

"At least he didn't die and we were able to interrogate him. That's why we're here. Not only to keep suspects from suffering debilitating injuries –"

"Lawsuits," Deeks coughs, which doesn't cover up his word in any effective way.

"– But more importantly these new guidelines are to protect every single one of you." Granger carefully meets the eyes of each person standing on the mats in front of him. "We'll always have people who'll break the law. It's not so easy to replace those who dedicate their lives to upholding it."

"Getting sentimental, Granger?" Sam asks.

"More like cost-effective." He clears his throat. "Do you know how much it costs to train agents for years and get them to the point where they have the collective experience this team has?"

"Aw, stop," Kensi teases. "You're gonna make us cry."

"How many of these sessions do we have to go through, anyways?" Deeks asks.

"As many as you need until I decide to pass you," Granger says, ignoring the complaints that follow his statement. As if he wants to be there any more than they do! He curses his inability to let Henrietta sign off on their evaluations, but when it comes to her team, 'lenient' is about the mildest he can call her. More like she'll let them do whatever the hell they want while she looks the other way, as long as they catch whoever they're chasing and complete whatever tasks they're assigned.

Granger has to answer to more people than she does, and he isn't going to let her rubber stamp things this time around. It absolutely doesn't have anything to do with his concerns about the ways some of them handle themselves in the field, or that he's checking up on them to ensure they don't stupidly get themselves killed (Eric Beale). Not at all.

Besides, maybe his presence will convince Callen and Hanna that he's serious about their evaluations this year and they have to tone things down. He's running out of creative ways to explain why they've shot people.

"You know an easier way to take down a suspect?" Callen flips through the manual – it has updated pictures of all the new 'field-tested' moves they're supposed to master. "Shoot them."

"Agent Callen," Granger rips the book from his hands and shakes it, as if to prove his point, "that is what we're trying to avoid."

Eric's been slowly inching his way backwards until Granger notices his movement and points at him to get back in line. He returns, muttering about how years of typing hasn't prepared him for this.

Nell knows Granger doesn't want her partnering with Callen for various (and admittedly valid) reasons, but that doesn't mean she's the best choice to partner with Eric. She sidles slightly to her left to whisper to Callen, "Switch with me."

He leans around her to catch sight of Eric wringing his hands and trying to get Hetty's attention on the sidelines for help. "Not a chance in hell. Good luck with him."

Nell doesn't deserve this. She's been trying to talk Eric down from his metaphorical ledge for nearly a week, ever since the new manual had come out, and he still thinks quitting might be a viable alternative to Granger's latest ultimatum.

Callen has no clue the kinds of things she puts up with on a daily basis, and after his refusal to switch, she decides to give him a taste of his own medicine. When Granger calls for his attention, she takes advantage of his distraction, hooking her left leg around his right one and pulling – she knows, even as she does it, that this is the kind of thing Granger disapproves of, and she doesn't care. Callen predictably loses his balance and (somewhat less predictably) grabs her arm to steady himself. She reflexively shoves him away, so when he falls, she goes down with him and they land in a sprawled heap on the floor, her slightly on top of him.

The room falls silent as everyone stares at them. Deeks frantically flips through pages in his copy of the manual. "I don't see that one in here. What's it called?"

"It's called 'Nell cheats'," Callen says, and she'd know he didn't mean it even if he didn't run a hand down her arm and squeeze her wrist before getting to his feet. As far as they're concerned, there's no such thing as 'cheating', although they still like to throw the excuse around as a means to antagonize each other.

"It's called 'you taught me how to do it, so you have no right to complain'," she counters smugly.

Deeks wonders how he and Kensi always win the prize for most complex relationship in those unofficial polls their co-workers annoyingly take. He says what everyone's thinking. "I believe it's called 'neither of you can play fair – ever'."

"We can definitely play fair," Callen argues as he stands over Nell. She's propped on her arms, in no hurry to get up. "We just…never want to?" It comes out as more of a question than he intends, and he glances at her for confirmation.

Nell meets his eyes and can't quite hide her smile. She wonders what goes on in his mind. Maybe even he doesn't know. "Whatever you need to tell yourself to justify it when I win."

In answer, he holds out a hand to her, only to pull it away the second she reaches for it. "I don't need to justify anything."

"Very mature," she says, sitting up and quickly wrapping an arm around his legs – he's made a critical mistake by standing so close to her, and they both know it. She can pull him back down again in a second. "Maybe rethink your position?" She means it both literally and figuratively.

"Sorry," he says, insincerely. "Your move was completely fair."

She considers tightening her grip on his legs and forcing him to lose his balance. He holds out his hand to her again; this time he doesn't pull it away when she takes hold. He helps her to her feet, wary the entire time for any move she might make against him. She can tell exactly what he's thinking.

Their eyes meet in a wordless conversation and no one moves until Sam clears his throat and breaks the strange silence that has descended upon the room. "Anyone that can take you down deserves respect, G. Even if you went down in the process, Nell."

Callen releases her hand and Nell steps back automatically. "Thanks, Sam," she says, as Callen shakes his head and mutters 'traitor' at his partner under his breath.

They've only been in the gym for fifteen minutes, and Granger knows he's in for a long day. "We haven't started yet. Point to Jones."

Callen doesn't appreciate that. "How does she get a point if we haven't started?"

"Consider it a reminder to keep alert, Callen," Granger tells him. "Isn't that one of your favorite rules? Criminals aren't out there announcing when they're going to come after you."

Nell moves back to Eric's side as Callen mouths 'I'm watching you' at her, and she infuriatingly waves back, as if she doesn't care. "It's on," Callen mutters. "It's so on."

Nell doesn't get very far with Eric before he darts off, insisting he needs to consult the manual, and Nell goes back to one of the benches on the sidelines. A handful of agents are at the end of the room on exercise equipment, a few more are scattered on the benches taking breaks from their own work-outs and watching the ones who are sparring as a form of entertainment. Kensi and Deeks are on the furthest mat at the end of the room, Callen and Sam in the middle, and her and Eric nearer to the door. This 'training' (and she uses that word as loosely as possible) is just for their team.

Her eyes don't stray far from the two men practicing on the middle mat and she can't help thinking about the past seven months. She's spent over half a year training with Callen.

They've become friends and it surprises her how much she likes it. How much she likes him. She can admit she'd been thrown. She had expected him to be a good teacher, but more along the lines of coldly efficient and deadly serious. She imagined him as being somewhere between drill sergeant and Hetty. So she'd been delighted to find that he was easygoing and approachable, right from the first day when he'd expertly set her at ease. Sessions wore on and she realized he wasn't just smart and capable, ruthless if he had to be, but also kind and funny. When he explained things, she just knew what he meant.

Over time, she went from viewing their training as a necessary obligation, to looking forward to their time together. And, more often than not, lately, their training is the best part of her day.

His manner shouldn't have surprised her, not after she'd seen the easy way he directed people. He had a gift for getting others to do exactly what he wanted, often without them realizing that it hadn't been their idea in the first place. In less than a week, the way she saw him changed. The respect was still there; the shift went deeper than that. It went to who he was as a person.

Talking to him was as easy as learning from him. They'd both found it astonishingly easy to carry on normal conversations while training. He'd shared things he hadn't told many people (she suspected that a few were things he hadn't told anyone). Sometimes he'd say something about himself, and then go quiet, like he didn't know why he'd said it. She would let it go, or share her own story, or make a joke to get him out of a dark place she didn't want him falling into.

In the second week, their sixth session to be exact, she asked how long he'd been able to fight, and he'd told her a story about one of his foster homes, having to learn how to protect himself from foster brothers that liked to jump him when he least expected it. "Don't know why they even used the term 'brothers', they'd just as soon have killed me if they could. That was a good home, though, only had the other kids to worry about and not the adults, too."

She'd pretty much stopped breathing when he said that to her. "You were eight years old."

He'd immediately noticed her unnatural stillness and moved closer to her where they were sitting on the mats. "No, hey," he winked at her, "I've always been fast. The ones I couldn't fight, I always outran." And the worst was how he said it joking, like that was supposed to make her feel better. It had been the first time she touched him that had nothing to do with their sparring. She couldn't stop herself from leaning into him and wrapping her arms around his middle as she put her head on his shoulder and tried not to cry. It had confused the hell out of him, too, until he took three seconds to process that she wasn't trying to stealthily pin him, she was just hugging him and nothing more. He'd carefully put his arm around her, and they'd sat there for a few minutes in a gym that suddenly didn't feel as cold as it had before.

After that, they traded stories as if it were a requirement of training together. He spoke of his past cases, the ones he thought she'd find interesting, whether good or bad. He didn't shy away from details once he realized she didn't need, or want, a censored version of his past. In return, she told him about her life up until NCIS. For a time, she shied away from stories outside of college, only occasionally sharing snippets about her family and growing up. Around session 12, when they'd both ended up on the mat, staring at the ceiling, he'd turned his head to say, "I wish you'd tell me more of your happy stories."

He somehow knew that she'd held back from tales of her idyllic childhood and loving family because he hadn't had the same. Until his reassurance, she'd felt guilty about telling him stories of her good life while he'd had one that should have broken him – that should have left him bitter and furious, blaming the world for his problems until he ended up in jail, or dead.

Instead, he'd clawed his way out and fought to be the kind of man no one had been for him as a child. He refused to let life break him, and used every painful experience to forge himself into one of the strongest people she knew.

Her thoughts were too much to keep to herself, no matter how embarrassing it might have been to admit the depths to which she'd thought about his life. So she'd told him how much she admired him (and why) somewhere around week five, as they sat on a bench in the gym, cooling off after a fairly standard lesson. He'd been quiet until she tried to leave, stopping her with a hand on her arm. He'd said that his past was what it was, and it made him who he was, and he'd never seen it as anything more than a regular life – sadder than some, sure – but nothing particularly special. He'd told her that her feelings, the way she saw him – he thought it said more about the goodness in her than it said about anything in him.

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