Disclaimer: I neither own Stargate or Numb3rs. Woot. I write this for fun, and nothing else.

Author's Note: This a cross between Stargate, around the time of early Atlantis season four, and Numb3rs, around the time of early season four. It's more of a numb3rs fic than a stargate fic, but I hope you enjoy it regardless of what fandom you follow.

I'm seriously not supposed to be writing fanfic right now, but this beastie screamed to come out this week. So I wrote it all up, and I'm posting it all at once, and I've done a quick edit so the grammar should be fine, and now I'm going to go back to what I'm supposed to be working on.

And if the science isn't exact, well, okay…it's a fanfic people! A fanfic!

Thanks in advance to everyone who takes the time to read it.

x.x.x.x.x

Rodney McKay glowered at the whiteboards. Actually, at this point, he was glowering at anything and everyone that dared to come near him. Which wasn't many. Noticeably, his lab had quickly become vacant of its usual occupants over the last couple weeks. If Rodney took the time to think about it, he probably wouldn't blame them, but right now he was just glad to be alone.

Every space, ever chair except his own, had been stolen for his use, because as much as it always seemed easier to display the problem on the multiple computer screens his rather sizable lab contained, Rodney found suddenly it wasn't enough. He had to see it in its entirety. Every aspect of the problem, every possible variation.

He figured he had every whiteboard Atlantis owned, but still it wasn't enough. Rodney had finally resorted to stealing from their small supply of paper, taping the sheets together and hanging them from the edges of desks, walls, whatever he could find to use.

To say it had become a small obsession of his was an understatement. But it was one of the most important obsessions a genius of his caliber could possibly have. They couldn't keep bouncing around the Pegasus galaxy without a reliable power source. At the rate they were going, and they certainly seemed to get in trouble enough to help matters along, they'd drain the energy they had faster than they could find it.

It all had to do with the ZedPMs. Even the Asgard's power source now entrusted to Earth with the Asgard's destruction wasn't a comparison to a ZedPM's power abilities. If the Ancients could make a ZedPM, they why oh why couldn't they?

As Sheppard would say, there were a lot of things the Ancients could do that they can't…yet. But Rodney's ego wouldn't allow for that kind of thinking. He was the smartest man in the galaxy, for certain in this galaxy of people's who's technology had been stunted by the Wraith. And, he was pretty sure, if he wasn't the smartest man from Earth, he was in the top three.

But no matter how he looked at the problem, he just couldn't figure it out.

What made things worse, was know he'd been the one to actually write the problem out in the first place. Due to an unfortunate accident, Rodney had first almost become an Ancient, long enough to spit several new equations out, only to loose any idea of what he'd been trying to say. Half of the symbols on the boards didn't even make sense. They were complete gibberish!

Even after six months of trying to figure them out.

Rodney glowered again, his hands searching for his long forgotten coffee cup as he stared at the board and it's current set of possible interpretations. If only he could figure out what the new math expressions represented.

"Rodney?"

"Umm?" He looked up to see Colonel Samantha Carter walk in, looking around with that half worried look she got sometimes, usually when she was about to reprimand him for something. He took a sip of the cold coffee only to spit it out again. He turned his glower on the offensive cup but then immediately refocused on the board. Numbers and equations and possibilities spread through his mind like a swarm of bees. He could multitask better than anyone, even her.

Rodney had known Samantha Carter back in the early days of the stargate program, had heard and admired her work even before then. She'd only been a Major then, now she was a full bird Colonel, in charge of this entire city, and still the best astrophysicist he'd ever met…aside from him of course, although his skills actually lay more in engineering physics rather than astro. In this job one quickly learned to broaden their field.

As the smartest woman from Earth, Rodney knew she did more than just see the whiteboards. Like him, he was sure she could see the math, too. "Still working on it, huh?" She questioned, trying to sound light even as her eyes roamed around the room, squinting with both the fascination of a fellow scientist, and the worry of a CO.

Rodney wasn't military, but neither was most of Atlantis, and it didn't make a difference anymore. Not out here, not where your lives seemed to hang in the balance everyday. "Something I can do for you, Colonel?" Rodney tersely asked.

"Rodney, come on. You need to take a break."

"No," he shook his head. "No, I'm on to something. I've got to think this through. People really should just leave me alone."

"Yes, and they have, for two weeks now. I know you're worried-"

"Stop!" Rodney sharply cut her off. "This had nothing to do with that." But the sudden pain in his chest betrayed him. Still, he continued on, "Atlantis needs this. We can't keep surviving without ZedPMs. Not with our odds. What are we supposed to do, keep stealing them from the Replicators? What if the Wraith win the war? What if we never find anymore."

"Rodney, we have a ZPM. Atlantis isn't in any danger."

"Not now, but what about in the future? What if we need to take the city into space again? Look at what happened last time? Are you going to tell me that's not going to happen again? No, Sam, we need this!"

She was quiet for a few minutes. "Do you really think you can solve it?"

And Rodney knew in that instant that she was analyzing him. His abilities, his time, his reasons for being here. Rodney knew he'd chased everyone out of his lab. His lab. It actually belong to his department, not a small number of people who not only put up with him, but worked with him. The problem was, normally this was really their lab because most of the time he was out on missions. It was such a different life than the one he'd imagined, even when he'd been working in Area 51, or in the Antarctic when Elizabeth Weir had first recruited him to head up all the science divisions. Technically, Zelenka had control of half of them now, but that hadn't always been the case.

And then there was the true issue he knew Sam was really weighing in her mind. As part of Sheppard's team they often got in trouble. Hell, Rodney had actually been shot in butt with an arrow once. It was a miracle he'd escaped their last adventure with only minor injuries. Only, the rest of the team hadn't. He'd heard Sheppard had finally been let out of bed, but Teyla and Ronon…

Rodney shook his head. "Of course I can," he snapped, answering her question. "If people would just leave me alone!"

"Rodney."

It didn't take much to make him wilt. Not from her. Both her and Sheppard had that ability. A single word and suddenly it was as if his ego had been crushed under the weight of his worries. How they did it he didn't know. It was probably some secret military training.

Sinking into his chair Rodney frowned. "Well it's not like I haven't solved it once before. For goodness sake, I wrote it!" He sighed. "I should have left notes for myself or something."

"You probably wouldn't understand them even if you had," she gently told him, leaning against the counter of the desk. "Ronon woke up today. You should go see him."

"And say what?"

"They're worried about you. We all are. And I know you're worried about them, but they're going to be fine. There was nothing you could do to stop what happened."

And once again she'd come right to root of the situation. His logical mind had told him this over and over again. There was no possible way he could have known what the machine did. No possible way to know the energy source wasn't just an energy source, but a living entity existing in multiple dimensions. No possible way to predict when things would go so completely sour. He should have been in the room with them. He should have been there. He should have figured everything out before the entity had manifested.

Doctor Keller had told him that they weren't dead, they weren't in a coma, and they weren't actually hurt, but it hadn't helped. And in the end, even after sorting everything out, there was nothing they could do but wait for them to wake up. They knew the rest would come out of their seemingly sleeping trance on their own. What had happened would pass, and as most alien encounters went, they were learning things the hard way. Which was why Rodney had felt so much need to fix this problem. They couldn't possibly protect themselves from everything, but with a ready supply of ZedPMs they at least had a fighting chance against most of the terrors the universe seemed to contain.

Too much time not normally spent standing still, or worse, filled with worry, had driven him to this problem. Obsessions like this hadn't happened as often as they used to, especially with the usual weekly demands of saving the day on his shoulders, but it was a great escape. He just wasn't sure if he was ready to admit it.

Rodney sighed. "I guess I should go see him." Sam smiled encouragingly, which normally could brighten even Rodney's worst moods, but a thought had suddenly struck the scientist. "You know. I know I could solve this. Of course I could, I'm me."

"But?" she slowly asked with a frown.

"Well, with all the demands on my abilities, I just don't have the time to devote to it." Her frown deepened, but Rodney was actually feeling a bit of excitement return. Yes, the more he thought about it, the more the idea seemed perfect. With a cocky smile he told her, "I do however, know someone who does have the time. And the brain to crack this." He actually found himself smiling, old fond memories surfacing from a long forgotten past. "He's no physicist, but he has a way with numbers even I can't match."

Now she really looked disturbed, and startled. Sometimes Rodney started himself. It took a lot for his ego to admit someone else's talents, but this someone held a special place in Rodney's childhood.

She finally had to ask. "Who?"

He grinned even harder. "A brilliant mathematician by the name of Charlie Eppes."

x.x.x.x.x

Charlie Eppes sat at the table looking over his father's homework. His father wasn't in any of the classes Charlie taught, much as he might wish, he was taking an engineering course instead, and Charlie was the Professor of Applied Mathematics, but he liked looking over his dad's work anyway.

The math was different, used more for structure and stability, and in Charlie's case wasn't even at a beginner's level, but the very act of helping his dad was something he really enjoyed.

It wasn't as if he didn't have his own student's papers sitting on the table next to him waiting to be reviewed, they just didn't have the same appeal of this.

A cheer went up from the other occupants in the room and Charlie looked up to see that one of the Dodgers must have just hit a homerun. His brother and his dad were on the couch watching a game Charlie had no interest in past a mild curiosity with the statistics, but it was still nice to have them all in the same room. Charlie couldn't help but smile. It was still amazing to him how different things had become. That they even had moments like these at all was a statistic rarity. Don's work didn't leave him much time for socializing, but his brother still dropped by whenever he could. Something that in and of itself never used to happen.

It was a hard reality that Charlie had to logically accept. Their mother's death had brought the family together again. Not only did they see each other more often, but also, Charlie helped Don with his FBI work on a frequent basis. It was as much a life-changing event for Charlie as it was a new thrill. To actually use his unique abilities with numbers and math to help Don catch real bad guys. It was so much more satisfying than even the work he'd once done for the NSA. There he'd still been an analyst. His algorithms and mathematical breakthroughs had increased their proficiency, and helped with issues of national security, but working for Don, Charlie felt like much more than just an analyst. Sometimes he even imagined himself to be part of Don's team. Not that he could, or would, want to help with a take down, or even half of the stuff Don did. He just liked knowing he was helping.

With a smile Charlie turned back to the work. It wouldn't take him long. The math really was very simple, and his dad rarely made few mistakes now. Writing a note of one problem, Charlie decided he'd wait till after the game to show his dad. He dad was really very adamant about learning how to do the math for himself, and he'd be distracted while the game was still on.

Chances were, Don would get called away again soon enough. Mentally Charlie kept a running tab of how often it really happened, creating a probability chart in his head based on various factors, like what kind of case Don had just finished, time of day, current rate of crime, and so forth. Something always seemed to come up.

Usually it was a ring of his cell, but this time it was a knock at the door that interrupted things. Still watching the TV, Don got up, telling their Dad to stay sitting, he was closer. Still doing the math in his head, noting the new inconsistent factor, and working through the problem on the paper at the same time, Charlie glanced at the door as Don opened it.

On the other side stood someone Charlie had never seen before. And rather uncharacteristically for a traveling merchant, he had a computer laptop bag strapped across one shoulder.

"Yes?"

"Hello Agent Eppes. I'm Colonel Cameron Mitchell, with the Air Force. I need to talk to your brother."

"Okay," Don drawled out and Charlie suddenly turned in his seat, giving the man at the door a new look.

He'd worked long enough with Don now to know when his brother was suspicious, and Charlie guessed he should be, too, but his curiosity was too high. He got up and walked to the door. "What can I do for you?"

"Professor Eppes, mind if I come in?" The Colonel gave him a genuine smile, but he wasn't in dress blues, and his brother tensed.

If there was anything Charlie had learned in the last three years, it was that he couldn't let curiosity make him naïve, not anymore. "Mind if I see some ID?"

"Of course," and the Colonel pulled it out ready to show. Charlie took it and looked at it with a calculating eye with Don doing the same over his shoulder. His brother seemed to relax some and Charlie took that as a good enough sign that this wasn't some kind of strange trap. That he even thought of things like that now proved just how much he'd grown. At least, that's what he liked to believe. He handed the ID back and stepped away from the door, indicating the Colonel could follow.

"What's this about?" Charlie asked, leading the man to the table. Don followed, keeping a cautious eye on the Colonel, and Charlie realized his dad had put the game on mute.

"It's a mater of National Security," the Colonel stated lightly, even smiling. "We have a math problem and we've been told you're the best Mathematician around."

Charlie felt a small rush from the praise, but modestly told him, "I don't know about that."

"No, it's true," Don suddenly stated, but he still looked like he was defending Charlie, Charlie just wasn't sure from what.

"Well," his father suddenly said, "Charlie, I can see you're going to be busy for a bit, so I'm going to go watch the game in the other room."

"Actually, Mr. Eppes," the Colonel said, stopping him. "I need to talk to all three of you."

Don crossed his arms, and giving the man a guarded look, dryly asked, "I thought this was a math problem?"

"It is. If we can sit?"

Charlie moved the papers to one end and the Eppes family took seats across from the Air Force Colonel. "What's going on?"

"Professor Eppes," the Colonel began and Charlie impatiently cut him off.

"Just call me Charlie."

"Okay, Charlie," the Colonel started again, "I know you have extremely high security clearance, but this math problem is very sensitive material and not some quick problem. Normally, for you to work on it, you'd have to do so on base."

Charlie felt both his dad and Don suddenly tense up. It was a testament to just how much things had changed. He'd spent the better part of a year with the NSA, and at the time had rarely seen anything of his family. But now, now he was a professor, the head of Mathematics at CalSci, and he really liked working with Don and the FBI. He could see it on the Colonel's face, if he took this assignment he'd be out of contact with his family for a long time, quite possibly, a very long time.

Charlie shook his head. "Then I doubt I can help you. I'm in the middle of too many projects to take on another."

"I know."

It wasn't the response Charlie was expecting. He'd worked with enough people on enough matters of National Security to know how it worked. Their problem always came first. This Colonel wasn't very much like them, and even smiled with understanding.

"I've read your file and I know how important your current work is." The Colonel didn't have to go into details, it was all implied.

Don tapped the table. "They why did you come?" Trust him to ask the direct questions.

"I've read all your files, and it's been agreed that all three of you can be trusted with this specific issue."

"I have a file?" Charlie's dad asked with surprise. Don just frowned.

The Colonel continued, "What I'd like to propose it that with chaperoning, Charlie would be able to work on our math problem here, in his own time, without our interference."

"Chaperon?" Don questioned.

"I'd have to stay with him or more specifically, the materials. Of course, it wouldn't be logical for Charlie to work on the problem and not expose you both to the work, so I'd need you both to sign a confidential agreement."

Having someone around him…a chaperone, as the Colonel had put it, was certainly unconventional and even a bit disturbing, but something else nagged at Charlie. "I'm assuming others have looked at this problem. Even if I can solve it, and that's no guarantee, it might take some time."

The Colonel leaned back, his posture perpetually relaxed, almost as if he were on vacation. "We know, and if you agree to the contract, I promise to be a good house guest. You will be completely compensated for any extra cost of having me here."

Here, here in the house. Charlie looked at his family unsure what to do. He wouldn't even be allowed to look at the problem until the contract was signed, and like any scientist, the unknown pulled at him. "Dad? You live here, too."

"It's your house, Charlie. Whatever you want."

Don didn't say anything, but Charlie knew from the thinning of his lips that his brother was cautious. The contract would have to verified, and this Colonel's identity confirmed, but Charlie didn't think they'd find Colonel Mitchell or his business was false. As unconventional as his showing up on their doorstep was, Charlie had already come to the conclusion it wasn't a hoax. Weighing the pros and cons of taking an unknown assignment for the Air Force, Charlie finally consented to what his mind told him, and his curiosity overpowered.

"Okay. Let's see the contract."

The Colonel pulled several papers out of his bag, Don made several calls, and their dad made iced tea for everyone. After an hour not only had the Colonel's ID been confirmed, but the Secretary of Defense himself had called to confirm the validity of the situation. That had shocked Charlie, and unnerved his brother, though Don was trying his hardest not to show it.

At long last they signed the papers and went over the details.

"I promise, most of the time you won't even notice I'm here," the Colonel stated, once again brightly smiling. "Due to the sensitivity of the materials, I must ask that you only work on this here at the house. I'll be copying everything you do into this laptop." He pulled it out and put it on the table, flipping it open and turning it towards Charlie. There was one noticeable difference. A finger print scanner next to the mouse. "There are only two people who can turn it on, myself and you. Go ahead."

Charlie reached out and put his thumb on the scanner. A barely visible laser read his print and the computer booted up. "I don't really use a computer," he said somewhat distractedly.

"I know," the Colonel said, grinning again. He turned the screen back around, telling them, "This computer can not leave my sight, even in the house."

"Paranoid much?" Don asked, but Charlie knew from his tone of voice that his brother probably didn't actually think that.

The Colonel seemed to notice that as well, and with another grin replied, "Better safe than sorry."

"Good words to live by," Charlie's dad remarked.

All the paper work was done, all the details hammered out, Charlie could care less about the time of night, his curiosity was over flowing so much his leg had started to bounce with his impatience. "So what's the math problem?"

The Colonel hit the keyboard a few times and spun the screen back around to face Charlie. The moment his eyes saw the familiar symbols and numbers he was entranced. He scrolled down, noting where one equation lead to another and others that seemed to be part of the whole were actually self-contained, having an effect on the full problem and yet not.

This wasn't like any other problem he'd ever seen before. Certain elements were familiar, but more weren't. It even contained symbols he'd never seen before, although his genius mind told him they were extremely significant. There were two things that popped out at him almost immediately. Half the math was in base 8, and the other half in base ten. And then a moment later he realized why this was considered classified. It was an equation for a power source. A power source unlike anything the world had ever seen before.

"Where did this come from?"

"I can't tell you that."

Charlie heard his brother begin to protest, asking why they signed the confidential agreements if it wasn't going to get them useful information, but Charlie interrupted him. There was something else he needed to know if he was going to solve it. "Did it work? Who ever wrote this, could they make it work?"

There was silence, enough that Charlie had to tear his eyes away from the tantalizing screen to see what the Colonel was doing. Apparently, the Colonel had been waiting for him. "Yes."

Feeling a shiver run up his spine, Charlie sat back, forcing himself not to look at the numbers again just yet. Sensing the sudden change, his brother demanded. "Charlie, what is it?"

"It's a power source." He replied without thinking. He didn't know how strong a power source, not yet, but at the glance, Charlie was sure it was incredibly high. He forced himself to look at the Colonel. "What happened to the person who wrote this?"

For the first time the Colonel didn't look so relaxed. There was a seriousness in his eyes that troubled Charlie. Not the kind to make him fear the man, more the kind to know there were things even his high security clearance wasn't going to reveal. Leaning forward the Colonel somberly told them, "We know it works, but we don't know how. It's possible the equation is incomplete. It's certainly not translated, and the person who wrote it…well, he was on the brink of death at the time." Then the Colonel stated very seriously, "I can't tell you how, but this power source could save millions of lives. Professor Eppes, will you work on it?"

He'd already signed the contract, so legally he'd already agreed to the job. That the Colonel was asking again spoke volumes to Charlie. He took a breath and replied, "Yes." Then, just like that, his mind turned back to the screen and all the numbers it contained. It was almost more than even he could contain. "I've got to get this up where I can see it." He grabbed the laptop and headed for the garage.

Only a small part of his mind actually heard his brother complaining, saying to the Colonel, "Couldn't you have waited to show him that till morning?" Or registered the fact that the Colonel was only a couple steps behind him.

Right then, his mind only heard the numbers. And they were talking really loudly.

x.x.x.x.x

The next morning Special Agent Don Eppes woke with a start, realizing a moment later that the alarm had gone off. Groggy, he rolled out of bed and falling easily into his normal routine, searched the closet for clothes before making his way to the bathroom. He'd spent the time at Charlie's, not really wanting to go home, or more pointedly, not really wanting to leave Charlie alone with Colonel Mitchell.

He was lucky Charlie and his dad had never converted his old room into a study. Coming out after his shower, Don found the house still and quiet. It concerned him for a moment, his instincts naturally tense, but then he heard the usual sounds of someone in the kitchen, and going downstairs found his father also awake and already eating breakfast.

"Hey, dad."

"Don, going in early, aren't you?"

"Do I have a normal schedule?" Don jested with a slight smile. His father just huffed and Don helped himself to some coffee and a bagel. He actually was going in a little early, but that's because he wanted to do a slightly more thorough search on this Colonel. Then, already knowing the answer, Don asked, "Where's Charlie?"

"Where do you think? He's still in the garage, been there all night no doubt." His father didn't seemed as perturbed by the matter as Don felt, but Alan had always had an easier time excepting Charlie's sometime eccentric habits.

Sitting down across from him, Don asked, "What do think of him? Mitchell?"

His dad shrugged. "Never had much love of the military, but he's polite enough."

For a man who used to be an active protester, this was a great accede. Don wasn't sure he was so gracious. "I hope this doesn't mean Charlie will be living out of the garage for the next couple months."

It was his biggest worry. He didn't understand the passion Charlie had sometimes, the obsession he got. He knew it wasn't harmful, knew that Charlie was working on several math problems he could never hope to even start to grasp, but every time his brother disappeared into the garage Don couldn't forget. He couldn't forget that barely four years ago Charlie had disappeared for three months into that garage, and at the time, nothing had gotten through to him. Logically, Don knew this was a completely different case. Then, their mother had been dying and throwing himself into math had been Charlie's way of dealing with it, only he hadn't dealt, he'd escaped. This was different, he knew, but Don still couldn't forget.

His father, sensing his mood as only parents can, looked up at him with calculating eyes. "I happen to have it on very good account that you both can be quite obsessive at times. Your brother will be fine."

"Yeah," Don said, looking away but not really feeling relieved. "I've got to go. Bye dad." He downed his coffee, and taking his bagel with him headed out.

He'd half expected to find the Colonel asleep on the couch, but it didn't look touched, and unable to quell his concerns, Don took a peak into the garage. It was much as he expected it. The staccato of the chalk as it hit the chalkboards echoed in Don's head and he looked around for the first time at what had consumed his brother enough to keep him up through the night.

Numbers and symbols decorated every available space. Other than Charlie, the only piece of furniture left was a small round chair where the Colonel had settled, the laptop open on his legs. He looked tired, but Don guessed it wasn't the first sleepless night the Colonel had had before.

Stepping fully in, Don turned his back on the Colonel and asked his brother, "How's it going?"

"Um? Oh, fine, fine." It was a lie, but not because Charlie was trying to lie, he was just too completely distracted to give Don any attention right then. He'd been there before. "You should probably call Amita and have her cover your classes for you."

"Yes. That's good."

Don didn't know if Charlie meant it was a good idea, or if he was talking about the equation he was working on, or if he'd even heard Don. With a sigh, Don turned to leave. "I'll see you later, Charlie."

Charlie didn't reply, but mumbled, "There's just not enough room. I need more space to write."

The Colonel spoke for the first time, replying, "I could call a friend and have him bring us a few more chalkboards."

Don's step hesitated. The Colonel's friend? He couldn't help his suspicions. Even with things confirmed, or the amiable attitude of the Colonel, contrary to anything Don expected of a military officer, he just didn't like having him there. There, alone, with his brother. But he knew he was being unnecessarily paranoid, and so forced himself to keep walking.

Perhaps it was because his mind was distracted, but Don didn't really remember his trip to the office, only that he was suddenly there, at his desk, using the FBI computers to pull up everything he could about Air Force Colonel Cameron Mitchell.

"Hey boss, you been here a while?"

Don turned to look up as Megan came into his portion of the bullpen. She had an eyebrow raised in question and leaning back, Don told her, "I'm just checking up on someone."

"What's the case?"

"No case." He saw the look of surprise and curiosity on her face and explained, "Charlie's working with the Air Force on a problem."

"Oh, is he going to be gone long?"

He shook his head. "No, he's still here. They sent a liaison to work with him here."

Megan smiled, and Don knew her profiling mind had already guessed what was really going on. Sure enough, she said with some humor, "And you're checking the guy out to make sure he's not a threat."

Annoyed and a little irritated by her all too keen perception, Don defended himself, saying, "I just want to make sure he's on the up and up. Yeah, so it's a math problem, but that doesn't mean he's not putting Charlie at risk. I mean, this is a matter of National Security or some crap." Don said the last bit almost sarcastically.

"Don," Megan stated, putting a hand on his shoulder, "I think it's great that you're playing the protective big brother."

But this only annoyed Don more, probably because it was true. "You know, it's not just that. This guy, most of his record is blacked out, he's Special Forces, I know it. And more than that, not only does he have the highest possible military security clearance, he's got the highest National Security Clearance. This guy has a get in free pass with every single government facility in this country."

"What?" Now Megan was getting it, and she leaned over his shoulder to see just what he himself had discovered. "What kind of math problem is it?"

Don almost groaned. "I'm not allowed to talk about it." Honestly, he'd already talked too much, but Megan wasn't one to nose things around, and he needed to vent his concerns to someone.

She regarded him with serious eyes, all humor gone now. And just like before, she got right to the root of his problem. "Do you trust him?"

With candid honestly, Don replied, "I don't know."

They didn't talk about it after that. In part because there wasn't much more to say, and in part because Don's phone rang and just like that it was back to work. For now at least, he'd have to keep his concerns in check.

x.x.x.x.x

Alan hadn't gone to his class that day. As much as he wanted to seem calm about the whole situation and respect Charlie's decisions, the truth was it was a little unnerving to have the Colonel in the house with them. So he'd stayed home, and when it became apparent that Charlie wasn't going, either, Alan had called Amita, explaining that Charlie was in the middle of something and could she cancel his classes that day. She offered to come over, but he quickly told her not to. Naturally, she'd become worried, so, wondering what he could really say, Alan told her that Charlie was doing some work for the government. Not for Don, but for the government.

She stopped protesting after that, but insisted she would drop by that night. Alan actually thought it was a great idea, hoping Amita could entice Charlie out of his trance. The two were going rather steady now, giving Alan high hopes of one day seeing them married and with children. Right now, Alan would just be happy to see Charlie take a break.

He'd taken food into the garage earlier, which the Colonel profusely thanked him for. Alan had the suspicion the Colonel was taking his job of 'watching' Charlie a little too seriously and wondered if the man had even left to use the bathroom.

Charlie had barely said hi and was continuously drawing and erasing numbers and figures on his chalkboards. Alan understood none of it. But as he was leaving, the Colonel stopped him, saying, "Oh, Mr. Eppes. A friend of mine will be dropping by later with a bunch more chalkboards. Hope that's okay."

"Yeah. It's fine." Alan wasn't sure if it was, he wasn't sure if it wasn't either, but he was glad for the heads up.

When the knock came at the door, Alan curiously opened it to find a tall African American smiling at him from his doorstep. He was a large and muscular man but it was hard to be too intimidated with the somewhat out of place cowboy hat on his head. He certainly didn't seem dressed like a cowboy. He didn't even have the big belt buckle.

"Are you Doctor Eppes?" he rumbled out.

"I'm his father, Alan."

The man acknowledged him with a nod in greeting that could almost be a bow it was so formal. "I am Murray. I've come to deliver chalkboards to Colonel Mitchell."

Alan found it a little strange how the man had pronounced 'chalkboards' slower, almost as if he hadn't really had to use the word before, but looking at the beefy arms, Alan figured it could be true. "Ah, yeah. They're in the garage."

Murray nodded again, and Alan followed him out, just to be sure. A van had been parked outside, and almost effortlessly, Murray unloaded the large black chalkboards. Personally, Alan thought they already had enough, but even Charlie lit up at the sight of them, half taking them from Murray in his excitement.

The Colonel had gotten up to greet his 'friend' with exuberance. "Hey! Murray! I'm so glad you could make it. You didn't get lost, did you?"

"I did not."

"Great, great! Thanks for bring the chalkboards. Any longer and I think he might have started writing on the floor," the Colonel half jokingly remarked, but Alan shivered, knowing it full well might have been true.

Looking with concern at his son, who was now filling up the new boards with a fervor Alan thankfully rarely saw, he wondered not for the first time if Charlie taking this job had been a wise decision.

"Then it goes well?" Murray asked.

Alan turned back in time to see the Colonel shrug, only to then grin. "It's like a vacation. And Mr. Eppes here makes the best sandwiches."

Alan wasn't yet convinced about the Colonel, but he couldn't turn down praise. "I have been known to make a stellar pastrami from time to time."

Again Murray nodded his head in his direction. The man certainly seemed to like to do that. Thankfully, he didn't stay long. And to his surprise, Alan found himself actually sighing with relief as the van pulled away. The Colonel and his son had already disappeared back into the garage, leaving Alan alone with his concerns. Unwilling to just stand around, he made a mental list of things he could get done around the house. Since he was home and all.

x.x.x.x.x

Charlie barely noticed the time passing. He barely noticed the food he knew he must have consumed. He even barely noticed that it'd gotten dark again. His mind was well and thoroughly consumed with the numbers. There were several problems he'd identified right away. Not because the math was unsound, but because it was being represented in a way he'd never seen before. And the fact that symbols, who's meaning he could only guess at, were scattered throughout the lengthy equation didn't help matters at all. Before he could do anything, he had to figure out what those symbols meant. And that meant coming up with various hypothesis, testing, testing, and retesting. It was far from being an easy feat. The symbols could be practically anything, but his mind thrived on patterns, seeing them where no one else could and so that was what he relied on now.

"Charlie?"

Amita's voice pulled him out of his thoughts the way a light could suddenly fill an entire room. He actually spun around in shock. "Amita?"

The Colonel was on his feet a second later. "I'm sorry Ma'am, but I'm going to have to ask you to leave."

"It's okay," Charlie quickly reassured the Colonel.

"No," Colonel Mitchell stated firmly, "It's not."

"Oh, right." National Security and all that. Seeing the angry look on Amita's face, Charlie quickly walked towards her, prodding her back into the house. "I'm sorry. You really can't be in there."

"I've worked with you on other cases," she retorted.

"This is different," and Charlie struggled with his natural desire to tell her everything, everything that had happened, everything about the problem, everything. "Hey, um, how did today go?" He asked, hoping to distract her even as he forced his mind to be still, working on the math problem only in his unconsciousness. It wasn't easy.

However, listening to her talk helped. She told him about her class, and his class, and a couple of the students who had come to her for help, and the students who had wondered when you'd be back to CalSci, and everything else. He smiled, drinking in her voice as she talked, and soon enough she was smiling back.

"Is it really something you can't talk about?" She asked suddenly, her eyes as curious as any good scientist, for she was a brilliant scientist, and someone who Charlie thought of as invaluable.

"Yeah, it is," he honestly told her, wishing with every fiber of his being it wasn't. She had ways of seeing things from a different light than him. Many of his inspirations had been from things she'd said while looking at his various cases. As Larry would say, solutions often come from the distant and unlikely voids of the universe.

Then his dad walked out and seeing them grinned, saying triumphantly, "I know it would work!"

"What would work?"

"Sending Amita to get you out of the garage. Even a great mathematician can't avoid the powers of a woman."

Charlie frowned but Amita laughed and as his heart lightened, Charlie wondered if it could really be true.

"Since you're out, how 'bout some dinner?" His father didn't wait for a response assuming it was a yes, and with a look around suddenly asked, "Where's that Colonel?"

Charlie looked around, too, realizing the Colonel hadn't followed them out of the garage. Curiously amused by the idea, he guessed, "Guarding the chalkboards?"

His dad raised his eyebrows in surprise, but then suddenly shrugged, saying ambiguously, "I'll take him something later." And then disappeared into the kitchen to probably make dinner.

Amita laughed again. "This is just weird, Charlie. You have a Colonel in your garage guarding your chalkboards? Something tells me the next few weeks aren't going to normal, are they?"

Charlie wondered what constituted normal, his mind naturally trying to calculate just that, and then had to agree, "Probably not."

x.x.x.x.x

One case, and then another, had been dropped into Don's lap. And both of them top priority. It was one of the problems with have the top team in the LA Branch, they got the most immediate cases and were expected to solve them just as quickly. What continually shocked Don was that they usually did. And in some ways he knew it was due to Charlie. Word had gotten around over the last couple of years about the LA FBI's Mathematician. Even here inside the branch Don caught mention of Charlie as being part of Don's team on a regular basis.

Part of him hated it, and part of him loved it, and both parts were usually kicked to the side as being inconsequential. They had a job to do, and if Don needed to use his bother's talents to help them he would. But now suddenly he didn't want too.

The first case had been easy enough, but the second gave them a lot more legwork. Twice now Colby had suggested they call Charlie for help, and twice Don had shot him down. It was only then he'd realized just how dependant they'd become on Charlie. Ya, Charlie could help, but he wasn't always going to be around, and he told them as such.

Even as Don snapped at his team he knew he was likely overreacting. Frustrated about more than they knew, Don got them going on their assignments. It wasn't like tracking down the whereabouts of few highjackers wasn't something they could do. It wasn't some great math problem, and certainly not something to be bugging Charlie about, not right now.

Don knew from conversations with his dad that Charlie wasn't closeting himself in the garage anymore, he'd even returned to CalSci to teach his classes. But his dad had told him every moment Charlie wasn't doing something he absolutely had to do, he was working on that math problem. They way Don figured it, the sooner Charlie had it solved, the sooner the whole matter would be done with and then Colonel Mitchell could leave and life could go back to normal.

Strolling outside, Don wasn't surprised to find Megan quickly catching up to him. "You should be following that lead on the truck, Megan. We've got a lot of ground to cover if we're going to catch these guys."

"I know, I will." At least she wasn't fighting him about the whole 'let's call Charlie' issue. Seriously, did they think Charlie could give them a magic algorithm to find all their bad guys? That's not really how it worked. But even Don felt antsy. He didn't think they needed Charlie on this one, but just knowing he wasn't accessible felt wrong.

He gave Megan a pointed look and turned to leave. He was trying to be as fair to his team as possible and run down as much legwork himself. Her hand caught his arm pulling him back and hesitantly she asked, "Are things…okay?"

He knew what she was really asking, the only one who knew why Don wasn't letting them call Charlie in on this, why Don was more tense than usual. "They're fine, Megan. They're fine." She just nodded, and letting go let him leave.

Don had to wonder if he'd lied to her. Nothing had happened thus far, and his mind told him nothing would, certainly Colonel Mitchell wasn't sinister in any way, but Don's heart couldn't shake the feeling that things were off. Something was off. And that usually meant at some point something would go wrong.

x.x.x.x.x

Charlie got up after only a couple hours, much as he had been doing for the last several nights because only exhaustion was letting him sleep at all. As hard as he tried, he just couldn't shut his mind off. The best he'd gotten was dimming things down, usually with Amita's help, so he could get through his classes, his lectures, and anything else that seemed absolutely necessary.

He had a class to teach today, at least, he was fairly certain he did. Checking the clock for the day, and the calendar for his schedule, he realized he had at least a couple hours of time before that, and almost eagerly made his way down to the garage. He'd shower and change later. One good thing about the Colonel following him everywhere, or Cameron, as the Colonel was now insisting on, was that he had a vehicle so Charlie didn't have to catch rides, or ride his bike. One thing he had never really liked doing was driving. His family was just fine to let that remain the case, telling him he'd probably get lost in a math problem while on the road. Something Charlie didn't feel the need to correct.

His mind already soaring with another possible equation or theory to try he stepped into the garage only to stop in complete and utter horror. Every black board was empty, wiped clean. Spinning around, he raced back into the house in a panic. Stumbling into the kitchen to find his father and the Colonel eating breakfast at the table, Charlie exclaimed, "It's gone!"

"What's gone?" his dad asked with immediate concern.

"My work! It's all gone, erased!" Charlie felt his knees go weak and he sank into a chair.

The Colonel wasn't nearly as shocked or alarmed as he should be, and with a tap to the laptop replied, "It's not gone, it's all in here."

"No," Charlie practically cried. "The chalkboards have been erased! All my new work, the revisions, my theories!"

"Yeah, it's all in here. I planned to put it back up again when we got back from the university," Cameron told him.

Charlie was shocked to realize he actually wanted to throttle the man right then. The Colonel seemed to sense it, too, because he quickly added, "I can put it back up now if you want."

"Why would you even erase it?" Charlie had demanded, half pleaded.

The Colonel's face scrunched up with concern. "I've been taking it down and putting it up every time we leave the house. Didn't you notice?" But Charlie hadn't noticed. Then the Colonel added in a smaller voice, sounding rather lame, "Plus, I was getting tired of sleeping in the garage."

His dad actually had the audacity to chuckle. Charlie just couldn't believe it. Had the Colonel really been taking the equations down and putting them up again? How could he not know that? How could he not recognize it hadn't been in his own handwriting? But Charlie knew how, when it came to difficult problems, all Charlie saw were numbers.

He slumped in the chair, suddenly feeling completely drained. He father stood up, giving Charlie a knowing look only a father could, and stated, "Why don't I make you something to eat."

He couldn't do anything but agree. Beside him the Colonel fidgeted uneasily, trying to act normal as he finished his own breakfast. Charlie still couldn't get the numbers to slow down, and reached for the laptop, but his father quickly stopped him. "Oh no you don't. Not at the table!"

Charlie actually sighed, but he relinquished to his father will. Wasn't this supposed to be his house? The numbers had finally dimmed again by the time Alan served him up a plate of fried eggs and bacon and just as suddenly Charlie realized he was starving. As he thought about it, he knew he had a long day ahead of him.

x.x.x.x.x

Alan sat at the dinning room table with his homework spread out everywhere. He had two papers due the next day, but he found he had a hard time focusing. His mind kept going over the last week. It was odd how he'd incorporated the Colonel into his son's daily life. Alan thought he might actually be getting used to the Colonel's presence. Cameron himself was really a rather pleasant guy. Easy manner, liked to joke but not tease, and was ever so polite. It was really a novel thing for Alan.

His son was also becoming more and more excited the further he got into this crazy energy source math equation. A physics problem, really, but to Charlie, math was math, no matter the application. Alan tried not to think about what the application might be for a 'power source,' especially one that the Colonel claimed could save million of lives.

Naturally, he didn't trust what the government thought was in the best interests of the people, and a power source that 'could save millions of lives' could just as easily kill those lives as save them. He sighed, once again trying to turn his mind to his paper, and once again finding his attention straying.

When the door opened, Alan turned to see his oldest son walk in looking strained, stressed, and plain exhausted. "You should have called ahead, I would have made you something to eat," Alan told him, trying to stay calm even as he worried over Don's condition.

"Nah. I'm not hungry," Don replied and Alan instinctually knew Don was lying, but didn't push it. Don sat down across from him, his eyes darting about the empty room, naturally going to the hall that led out to the garage. "Is Charlie around?"

"He's at the university. Why, you need his help on a case?"

"No. I was just curios. He there alone?"

"No, Cameron's with him." Seeing the look on his son's face, Alan put his pencil down. The paper could wait. "You know, Don, I don't think we have to worry about the Colonel."

"Yeah, I know," Don replied, but he was fidgeting.

Alan picked up his pencil again, no mind for the paper, but knowing his son didn't want to talk about it. Still, he couldn't help but say, "Charlie's a grown man, Don."

As he expected, Don got up, his mannerisms radiating irritation. "I know that, dad!" Don disappeared, but Alan didn't have to turn around to know Don was getting himself a beer from the kitchen. He always did when he was upset about something, but Alan had learned the hard way that if he didn't chase after his son, he'd come right back. Sure enough, Don reappeared, sitting back down at the table and taking a swig of the beer as Alan tried to look preoccupied with his homework.

He gave it time, and after five minutes of silence it finally came out. "This last case took us five days. The guys almost skipped town before we caught 'em."

Alan glanced up but Don wasn't looking at him, he was staring in the direction of the hall, in the direction of the garage. After another minute of drowning silence, Alan finally prodded, "You got them, right?"

"Yeah." Once again irritation creased his face. "It's just, I just can't help thinking…" he trailed off, obviously struggling with something in his head, almost unable to give the voice thoughts. Alan had a feeling he knew what it might be. He's seen a lot of changes in his sons over the last three years. Some for the worse, but most for the better. Then Don tried again, saying, "I bet if Charlie had been in on it he'd have come up with some fantastic mathematical way to predict where these guys would have been."

"Or he might not have," Alan stated simply, trying to be the voice of reason to Don's self doubts, but he knew his son wasn't listening. Him and Charlie were too much alike in that respect. Far too obsessed over their own guilt. Personally, Alan had wondered where they'd even developed that tendency. Certainly not from Margaret or himself. Still trying to sooth his eldest son's worries, Alan firmly stated, "You did catch them. It's what you do. And you're damn good at it!"

Don actually smiled, looking a little more like himself. "Yeah, we did get them."

"Good." Alan put his pencil down again. "Now, how about I reheat some of the turkey soup I made the other night."

Again Don smiled. "Sure dad."

Alan like having his sons around. Liked it even more when they let him be a parent again. It wasn't easy, one son a world renowned genius, the other, a world renowned FBI Agent, and him in the middle, thinking the world of both of them. It was too bad Margaret couldn't see the impact she'd had on them.

By the time Alan had brought the soup out Don had showered, changed, and looked far more human than he had before. They sat down to share lunch, Alan's second lunch, but he wasn't going to miss the opportunity of have a meal with his son. Then, as Don took a sip of the soup, he not quite so casually asked, "So has Colonel Mitchell been using my room?"

Alan pretended he didn't notice Don's discomfort and told him with candid honesty, "No. I offered it, but Cameron refused. Actually, for the first half of the week he was sleeping in the garage. He's since moved to the couch. I'm a little worried about him. He insists on being awake whenever Charlie is, and well, you know Charlie when he's got his mind wrapped around a math problem. He doesn't sleep much."

"You're worried about him?" Don asked incredulously, making such a face that Alan wanted to chide him for it, only barely refraining from not.

"He's a decent man, Don," Alan stated instead, a little surprised to find himself standing up for the officer, and even more surprised at Don's reaction. "I don't think he would harm Charlie."

"I know, I know." And it sounded an awful lot like Don had been having that same argument with himself for some time. Looking contrite, Don told him, "I don't think he would either, it's just…I just don't like it."

It, not him. Don didn't like the situation, and in many ways, Alan would agree. But at the same time, he'd seen both his sons go off into many situations he didn't like. That was the nature of their skills and professions. "Sometimes it's not about what we like, Donnie."

Don made another face but didn't reply. Instead, he buried himself in eating his soup. Alan slowly had some as well, but made no real effort. After all, he wasn't actually hungry. All too soon Don was finished and standing up, he said, "Thanks for lunch dad. I think I'm gonna go home and crash. Been a long week, you know."

Alan didn't believe him for a second, but he didn't want to push Don too hard. "Hey, stop by anytime. There's a game on tomorrow night."

"I'll see if I can make it," but it wasn't a promise. Even without the recent complication in their lives, Don was perpetually on call, and was called, perpetually. Alan watched as his son left again, glad Don had even stopped by at all. He sighed. No, sometimes it really wasn't about what a person liked.

x.x.x.x.x

Don had intended to go to CalSci, just to check in on Charlie with his own eyes, but he barely got two steps outside the house before his phone rang. "Eppes."

"Don, we've got another case. Walt wants you in right away," Megan's voice told him over the phone.

Idly, he wondered if she had even made it out of the office, while consciously he replied, "I'll be right there." He shut the phone and sighed. This really wasn't one of his better weeks. Ignoring the weary feeling seeping into his bones, Don quickly made his way back to work.

Megan met him practically at the elevator, but she wasn't alone. "Don, this is Agents Malcolm Barrett and John Grey with the NID."

"Hey, Don Eppes," Don greeted, his mind already switching back to his 'work' frame of mind. Agents from another Government Agency always meant it was something big.

Barrett, apparently the head of the two immediately got down to business. "We've been tracking a man by the name of Tom Weavers for some time now. We think he might be in LA."

"What's he wanted for?" He led the group back to his desk, and then redirected them to one of the conference rooms. As he did, he noticed Colby and David exiting the elevator and motioned for them to catch up.

Barrett waited till everyone was in the room and the door shut. "The main charge is the selling of government secrets, but he's got a history of being a mercenary for hire."

Crossing his arms, David asked, "How do you know he's here?"

"The NSA intercepted a message we traced back to LA. The location had been abandoned, but we're pretty confident that he's still here."

"What was the message?" Don asked.

To his surprised Barrett shrugged. "We don't know. It's still encrypted. The NSA are still working on it, but they say it's a new style of encryption they haven't encountered before."

Don filed that away, saying with doubt, "We can have our guys take a look at it."

"Actually, that's part of why we're here. A friend in the NSA said you've got a mathematician that helps you out, and has worked with the NSA on encryptions before? Your brother?"

Don felt his jaw tightening. "He's a little busy right now."

"This is important. I'm sure Weavers is here for something important, and we need to know what it is."

Everyone in the room was watching him, the NID with cautious hostility out of their need to push this forward, and his team with just plain caution. They knew how protective he was about his brother right now. Thinking it over with thin lips, Don knew this wasn't something he could pass over, or even begin to think they could solve without Charlie. With half a sigh, Don finally said, "I'll see if he can help. In the mean time, I'd appreciate any other information you have about Weavers so we can start trying to track him down."

His team gave a collected sigh, forgetting their own weariness as they all got started on the new case. There was always a strong chance they could find Weavers without the decoded message, and it was something Don rather hoped could happen now, but once he'd gotten his team going on assignments assimilating the information packet Barrett had brought, he knew he couldn't keep avoiding the inevitable.

Barrett had actually wanted to come with Don, but Don absolutely refused, saying he'd bring Charlie there if he were available. He didn't just want to call Charlie in. For some reason he couldn't explain, Don's unease had started to grow. He needed to see Charlie himself on this one.

A short ride later had him at CalSci and with almost brotherly instinct, Don found the classroom on his first guess. He slipped inside, spotting the Colonel sitting at an angle so he could watch both Charlie and the door. Don wondered if it was conscious or habit bread from experience. Much of the Colonel's history had been his stellar record as one of the top pilots in the Air Force. It was only the last few years that had been completely missing, but Don knew even a fraction of that time in the right situations could change a man's life forever. Not unlike his own time in Fugitive Retrieval.

Walking in and sitting next to the Colonel, Don noticed the laptop bag was still around the Colonel's shoulders. He was never without it, but Don was surprised to see the Colonel still wearing it instead of keeping in on the half desk in front of him. The Colonel's words from the first night echoed through his mind. 'Better safe than sorry.'

"Agent Eppes," the Colonel murmured in greeting.

"Colonel Mitchell," Don returned. They didn't say anything else, but each turned and listened as Charlie continued his class. Don could tell it was almost over. He knew also that his brother had seen him enter, and that look in his eye told Don Charlie knew something was up, but Charlie didn't pause, and soon his body language changed back to the casual excitement he always had when teaching. It was one of the things Don secretly like watching. He didn't care if Charlie could solve some of the greatest mathematical mysteries the world had, he just cared if Charlie was happy. And watching him, like this, helped Don believe that maybe his little brother was.

When the lecture ended the rest of the students got up, leaving in a cluster of noise and motion. Both Don and the Colonel remained seated. When the class finally emptied, Charlie walked up to them, books in hand and a smile on his face. "Hey Don."

"Hey Charlie." Decided he didn't want to dance around the issue, or that he was a little too tired to do so, Don decided to just blurt it out. "Hey, look. We've got a case, pretty serious situation. Hired mercenary in LA, and we don't know why. NSA intercepted a message from the merc but they can't break the encryption. Your name came up."

"You want to see if I can break the code?"

"Yeah."

Don waited, watching his brother with calculating eyes. Charlie didn't immediately jump on it, but he also didn't turn it down. Then Don saw Charlie's eyes flickered to the Colonel and the Colonel retorted, "Hey, it's up to you. I'm in no rush."

Don wasn't sure if he was annoyed at the Colonel, or just that Charlie had felt the need to ask him permission. Once again he felt his jaw tightening in distaste, but then Charlie said brightly, "Yeah I'll help. I could use the break."

Highly doubting that was the case, Don watched the emotion play across Charlie's face. He wanted to tell Charlie he shouldn't help, that he should just stick to this crazy math problem of his like his face said he wanted to, but he knew his brother well enough to know that would just crush him. He didn't want to stop his current work for this, but he didn't want to let Don down, either.

It was almost comforting to Don to find out he rated higher than an engaging math problem. He just wished it hadn't had to come up. "Okay. Thanks."

They followed him back to the Branch Office, both of them. The Colonel's ID cleared both him and the laptop through without search or fuse much as Don assumed it would, but when the elevator doors opened to let them out on the right floor Don felt the Colonel suddenly stiffen in surprise.

Across the floor, the NID agents turned and seeing them, it was obvious Barrett was having an equally shocked reaction to seeing the Colonel. It had passed by the time they reached the others, but Barrett still greeted them with a tight smile. "You must be Professor Eppes. I've heard you do fantast work."

"Thank you," Charlie answered simply, but even he had notice Barrett hadn't actually looked at him.

Then the Agent greeted in a low and almost ominous voice, "Colonel Mitchell."

"Agent Barrett," the Colonel returned, sounding just as guarded, and Don's internal alarms suddenly rose. There was no obvious hostility, but the amount of distrust the two men had for each other was thick.

"I'm surprised to see you. What are you doing here?" Barrett asked diplomatically.

Mitchell smirked, replying lightly, "I'm on vacation."

"Really," The two men were so locked in their gazes it seemed to freeze the moment. Don opened his mouth to either break them up or demand to know what the hell was going on when Agent Barrett asked, "Colonel, can I have a word with you?"

"Sure," Mitchell replied, keeping his voice light, but the skin around his eyes were tight. They moved off a ways, but not so far that Don couldn't hear them.

"What are you doing here? Seriously," Agent Barrett practically demanded of the Colonel.

"It's nothing. Seriously," Colonel replied, his eyes hardening, but not with malice as much with annoyance.

"You know the NID is supposed to be informed of any-"

Mitchell cut him off, saying emphatically, "The world is not in danger!"

It was an odd thing to say, a little melodramatic, but even odder was that Barrett seemed to take it seriously. "You're not just lying to me, are you?"

"I'm not just lying to you," Mitchell insisted and after another minute of staring at each other, the two men walked back.

"I'm sorry," Barrett apologized, his demeanor completely changing. He gave Charlie a huge smile. "Professor Eppes, it truly is an honor. We could really use your help with trying to decode this message."

"That's what I'm here for," Charlie replied, confusion creasing his face as he looked at the two men who'd been quietly arguing only moments before. There wasn't even a trace of agitation left on either man's faces.

Glancing at Barrett's partner, Don noticed even he had been surprised by the encounter.

"Well, let me show you what we've got," Barrett said, leading Charlie further into the bullpen, to the room Don had set up for them to work in. He was about to follow, but a hand caught him and he looked down at Megan. She'd heard the argument as well, and with a single expression had communicated everything she was feeling to Don, mostly because it mirrored his same thoughts. Something was up, and whatever it was, it wasn't good.

Don just wished he knew what.

x.x.x.x.x

Charlie sat in front of the screen Agent Barrett had left him with in the corner of one of the rooms. It was easier to do this work without the distraction of the bullpen, plus, if he could hear the things Don's team was doing on their end to track down their current bad guy, even Charlie knew he was likely to get distracted. But regardless, things still insisted on interrupting his thoughts. Mostly, the phone.

First a call from his dad to find out why he hadn't come home from the school, then a call from Amita wondering if he was still at the school, another call, surprisingly from Larry, who'd gone to the house only to find he wasn't there, and again another call from his dad inquiring if he planned to come home any time that night.

Charlie wasn't a believer in Murphy's Law. As a mathematician, he just couldn't give way to the idea that bad luck followed good deeds. As a boy he'd even gone out of his way to disprove the theory, but it certainly seemed uncanny that his phone rang every time he felt he was close to a breakthrough. If he thought about it, he'd realize he was just impatient. He wanted to crack this a fast as possible so he could get back to the real project swimming in his head.

But it was with guilt that he hung up with his dad, having already apologized on the spot for getting short with him, especially when he realized it was already one am. Sometimes this office could be as disorienting as the computer labs were at night at the school. With chaotic events plaguing them daily, it was no wonder the office was still full of people, but a hour later even that finally seemed to thin.

Then Don came in, looking bushed. "How's it going, Charlie. Got anything yet?"

"No, not yet," Charlie replied in a terse tone. He was vaguely aware of the Colonel spinning in his chair somewhere behind him, but he'd tuned near everything out in his focus.

"Charlie."

It took a second time before Charlie actually turned and looked up at his brother.

Don pursed his lips, the way he did when he had something to say but didn't want to say it. "Why don't we take a break. I've already sent the others home to catch a couple hours, we should do the same while we can."

"I'm really close, Don. It's like I know how it's encrypted, I can feel it there, right at the edge of my brain, I just can't seem to think clearly enough." And he kept getting distracted, although he didn't say that part out loud.

"I know you'll get it, Charlie. But maybe it's not coming because you're tired."

Charlie hadn't been tired until Don said it, and then like a magical word the exhaustion set in. His brain slowed down, the numbers stopped trying to overpower him and for a moment he wondered if he would fall asleep right then and there. "Yeah, okay. I could use a couple hours." He got up, moving sluggishly away from the computer.

Of course his brother smiled. "Yeah, there we go. Maybe dad'll make us breakfast."

Not bothering to reply, Charlie stumbled out ahead of Don. He could feel the Colonel moving along behind him, but he'd gotten so used to the Colonel being in his peripheral vision it didn't even bother him anymore.

Don drove them all back in his car, and Charlie was sure he would have fallen asleep along the way if Don hadn't suddenly started asking the Colonel questions. And just like that Charlie was wide awake.

"So, Colonel Mitchell. What is it with you and Agent Barrett?"

"We've worked together a few times," Cameron casually replied.

"On good terms or bad terms," Don pushed.

Charlie couldn't see the Colonel, but he imagined Cameron shrugging the way he often did when he was being evasive. "Both? We've had our ups and downs I guess you could say. But Agent Barrett's a good man if that's what you're asking."

"It's not." And the tone in Don's voice caused Charlie to look at him in surprise. His brother's eyes were narrowed, tight, and while he looked calm and relaxed, Charlie had seen enough of his brother in action to know he wasn't as relaxed as he looked. Then Don added darkly, "This guy we're chasing, it doesn't have anything to do with you or this math problem, does it?"

"Not that I'm aware off. It's pure coincidence Barrett and I know each other."

Don huffed, not fully believing that. Charlie wasn't exactly a firm believer in coincidence, either, not when more times than not it could be mathematically explained.

Then Don asked something else that startled Charlie. "So this math problem Charlie's working for you, this power source, what's it for?" Charlie had never known Don to be quite so directly hostile before, unless he was in an interrogation room.

"I can't tell you," Cameron stated, his voice sounding much like he'd been expecting the question for some time. "But I can promise you, Agent Eppes, it's nothing that you could possibly imagine. We're not the bad guys."

Don didn't reply, but his lips thinned. Frowning, Charlie turned in his seat to look back at the Colonel. "I have the highest security clearance, don't I?"

Cameron actually smiled at him. "That doesn't mean you need to know, Charlie."

The rest of the trip was silent, which both dared to wake Charlie up as it did want to put him to sleep. His brain kept thinking, keeping him awake, but it wasn't about numbers, it was about what Don had asked. What was the power source for? He'd learned enough by now to know that the potential output was enough to run half the world. Just learning that was enough to fill his mind with unwanted worries.

x.x.x.x.x

Alan looked around the table, ecstatic. He'd been dozing on the couch when his sons had come in, but had quickly relinquished the couch to the Colonel and gone to find his own bed. Now, while only a couple hours later, they were all up and at the table eating pancakes. No one was really talking. He was sure Don was focused on whatever case they were in the middle of, and if Charlie wasn't focused on that, no doubt he was thinking about the math problem. Cameron hadn't said much himself past a few compliments to Alan about the food, but seeing him give Don several furtive looks, Alan was convinced his eldest had somehow intimidated the Colonel. Don could have a way of doing that from time to time.

Regardless, they had a full house, and that was a rare event to be celebrated every chance possible. "So, how's the case going?" Alan asked, not really expecting an answer but needing something to break the silence.

Don replied, "It's going okay. We've got a few leads that seem promising."

"I think Charlie's almost got that encryption," Cameron cautiously added.

Charlie didn't reply, and one look told Alan he wasn't going to. It was amazing the fork was managing to find the mouth, Charlie's thoughts had gone so deep. Then suddenly he jumped up, crossed the room and came back with a blank page torn out of one of Alan's notebooks, at least, Alan seriously hoped it'd been a blank page. "Charlie, come on, not at the table," he complained, but his son didn't hear him, the pencil was already moving in one hand and the fork moving in another.

Then it all suddenly stopped, and around a mouthful of pancakes Charlie exclaimed, "That's it!"

"Solved your big math problem?" Don asked and Alan was sure he detected a note of hopefulness in Don's voice.

"No," Charlie replied, swallowing hard to clear his throat. "I've still got a long way to go on that one. But I know how the encryption was done. I should have seen it before. I mean I've been going over so many theories and different equations trying to figure out those unknown symbols that it's all right there in the front of my brain. I should have seen it before." He repeated, still staring at his notes even as the words came tumbling out.

"Okay," Don stated, standing up, and Alan knew that was the cue. The end to breakfast. "Let's go."

"What?" For a moment Charlie just blinked up at him, but then he suddenly sprang into motion, likely anxious to test out his theory. "Thanks for breakfast, dad."

"Yeah, thanks dad," Don echoed already looking for his suit jacket.

"Will I see you boys later?"

"Of course," Don replied, but there would be no mention of when.

The Colonel rose, too, not so willing to leave his breakfast half eaten as he hurriedly shoved the last of his pancakes in his mouth. "Thanks Alan for the pancakes, they were great."

"Don't talk with your mouth full," Alan lightly chastised, earning a grin in response. If only his boys were so appreciative of his cooking.

Alan really didn't mind, but sometimes he felt like this house was nothing more than a rest stop to them.