A/N: I started working on this oneshot BEFORE the 1-15-10 episode, "Arm in Arms". Some similarities will be noted; I assure you, they are purely accidental.

Disclaimer: Numb3rs is owned and operated by CBS, Heuton, Falacci et al (no cats involved).

Best Man
by Fraidy Cat

The shock and surprise that Charlie felt was only evident in his eyes -- which kept growing larger. Don thought the pupils were even dilating. Sitting in a comfortable chair in Charlie's office, facing his brother across a huge, solid oak desk, the hardened FBI agent swallowed in nervousness. He had been positioned with one foot crossed over the other knee, leaning back in the chair; now, he planted both feet firmly on the floor and hunched forward. Distractedly, he rubbed sweaty palms on his denim-clad thighs and cleared his throat. "Charlie?" he croaked. He cleared his throat again. "You heard me?"

Charlie blinked, and it struck Don that his brother hadn't done that in quite some time. Charlie spoke around a polite smile. "Congratulations," he said, the monotone of his voice belying his next words. "This is very exciting."

Don felt the heat of embarrassment color his face, and he rose to his feet. "I knew this would happen," he whispered under his breath. His voice was sincere as he looked down at Charlie, who was still seated. "I'm sorrry."

He hadn't thought Charlie could look any more surprised, but somehow, the mathematician managed. Charlie waved his hand in front of his face as if he were swatting at a mosquito. "Sorry?" he asked incredulously, looking up at Don. "What on earth for? Sit, sit; I'm getting a kink in my neck."

Apparently, Charlie was able to string together sentences again; perhaps that was a good sign. Don tried to grin, but the result was pretty wobbly -- as were his legs. He dropped heavily into the chair, leaning forward far enough that he could prop his arms on Charlie's desk. He clasped his hands together in a gesture of subconscious supplication. "It was never my intention to rain on your parade. That's not what this was about."

Charlie remained silent, but confusion was starting to push the surprise out of his expression.

Don explained further. "I mean, I know you and Amita are planning a big wedding. Dad's almost as happy about that as you are. He'll still be happy, Buddy, even after he hears the news."

This time, Charlie rose to his feet. Confusion and surprise alike had given way to stone. "I don't know what you're talking about," he announced gravely. "I'm not at all concerned that you've somehow...usurped my position. I sincerely congratulate you."

Don was back on his feet, as well -- and he wasn't entirely sure when that had happened. He had tried to be nice. Now, Charlie was bringing him down -- and starting to piss him off. He huffed in sarcasm. "Try to control your enthusiasm." He half-turned toward the door, intending to leave the Cal Sci office and get back to a happier life. "I just wanted you to hear it from me. I'll leave you to your...whatever."

Charlie jolted forward a step and managed to latch onto Don's arm. "I'm not upset about my wedding to Amita," he insisted. "If anything, what you did will just make everyone appreciate a ceremony that much more."

Scowling, Don faced his brother, shook Charlie's hand off, and crossed his arms over his chest defensively. "Save it," he suggested. "I'm not buying what you're selling. You can't stand there and convince me you're not upset."

Charlie dropped his gaze to the floor and ran a hand through his curls. Don started to turn, again, but Charlie looked up quickly and choked on his reply, as if he had bitten into a lemon. "It's not... Stop!" Don did, but did not turn to face Charlie again. Charlie sighed, then almost whispered. "I...just wanted...to be your Best Man."

Almost against his will, Don's head swiveled on his neck. "What?"

Charlie's face was beet-red. "All my life, I've had hopes that...you and I would be close enough, by the time you got married..." He kept his eyes on his shifting feet. "I hoped you'd want me to stand next to you."

Don's arms lowered, as did his defenses. If he hadn't been fresh off a weekend in Vegas that left him married -- to Robin, thank God -- and still deliriously happy about that development, he probably would have been able to more successfully disguise his response. "Hmpf," he huffed. "Funny thing for you to say to me, don't you think?"

Obviously, Charlie had not anticipated that answer. He had begun to look a little vulnerable with his earlier admission; now he looked very vulnerable, legitimately confused, and slightly wounded. The combination was nearly lethal, and Don's eyes skittered away from his brother. Charlie was apparently struck speechless, so Don continued with a speech that sounded lame in his own ears. "I mean, I sort-of hoped the same thing...but I guess you asked Larry to be your Best Man..." He snuck a glance at Charlie, saw only his back. He was headed for his chair behind the desk. Don shifted his feet, finally began an approach toward his own vacated seat. "Not that I have a problem with your choice," he mumbled, sinking into the over-stuffed chair. The butter soft leather welcomed him home. "He's been your best friend for years."

Charlie sat with his elbows on the desk, his hands tented before his face. He was silent for so long that Don decided he had been dismissed. He gathered his legs beneath him and prepared to stand.

Charlie's hands dropped flat onto the surface of the desk. "I have two things to say in response to that," he said, introducing his reaction as if he was preparing to start a freshman lecture. His chair began to swivel gently, and he let his hands fall into his lap. "One is that we are both idiots. I begin to understand why Dad so often despairs." Don arched an eyebrow, but had long ago learned not to interrupt the professor midstream. He waited.

He didn't have to wait long.

"The other," continued Charlie, "is an apology. I apologize for...being myself."

Don couldn't let that one pass. "What the hell are you talking about?" He tried to sound grumpy.

Charlie tilted his curly head to one side, then righted it again. "I've been completely distracted. The usual responsiblities of school and consulting, teamed with the unusual stressors of calculating the logistical components of intended matrimony..."

In spite of himself, Don laughed. "Now that I think about it, I completely understand why you would want Larry as your Best Man. You speak the same language."

Charlie reddened slightly. "Don't be an ass," he pouted. "Was that clear enough for you?" He huffed when Don laughed again. "I'm trying to tell you that I did not ask Larry to be my Best Man."

Well. The laugh died in Don's throat. At least he could understand choosing Larry over him -- but someone else?

Charlie correctly interpreted the crestfallen expression on Don's face. He spoke gently, sincerely. "I've never considered anyone but you. Yes, Larry has been my best friend for many years -- but you have been my brother forever. You share my history, as well as my present, and, I hope, my future. My wedding would be incomplete without Amita there as my bride; and just as incomplete without you there as my Best Man." He sighed. "I see now that I just assumed you would be there -- I never actually asked. That was my error, and I sincerely apologize."

Don felt a sensation of warmth in his chest and moist heat behind his eyes. He was about to embarrass himself when Charlie suddenly slipped from his chair, knelt on one knee at the end of his desk, and offered Don a piece of chalk. "Donny. Would you be my Best Man?"

A burst of laughter erupted from Don. "Get up, you idiot," he said fondly. As Charlie grinned and began to scramble to his feet, Don also stood. "I want you to know that if I'd had a Best Man, it would have been you. Honestly -- I'm not just saying that."

Charlie, standing now, just a few feet away, was still grinning. "Okay," he said easily. "I'll choose to believe that."

Don shook his head, both marveling at and treasuring his brother's simple faith in him. Or maybe, Don mused, given all they'd been through to get where they were, complicated faith would be a more accurate description. "You know," he finally said, "the Best Man usually gives the groom a bachelor party."

"You are no longer a bachelor," Charlie pointed out.

"Robin's girlfriends are going to throw her one of those shower-things," Don argued. "It'll just be, what? Posthumous."

Charlie's eyes crinkled and he sputtered a laugh. "My God," he choked. "You're married — not dead!"

Don grinned. "Jury's still out on that." Charlie groaned. "Seriously," Don continued. "I propose a little friendly competition. Which one of us can throw the best bachelor party? Ground rules: nothing illegal, nothing that will potentially end up on the front page of the Times."

"Nothing that will lead, directly or indirectly, to a divorce settlement," put in Charlie.

Don nodded. "Agreed." His eyes began to twinkle. "Should we invite Dad?"

"I think there have been enough misunderstandings in this family already, don't you?" answered Charlie.

"Good point."

Charlie pivoted and started rapidly for his chair. "Sit," he ordered. "Take out your cell and access the calendar. We've got to find two dates that work for both of us."

Don rolled his eyes, pulling his phone off his belt as he headed for his chair. "Great," he grouched good-naturedly. "Something tells me this will be the hardest part."