Author's Notes:

Hello, welcome and thank you for checking in!

First of all, this story would never have reached its current state without the invaluable and selfless help of OughtaKnowBetter. She inspired me to complete this story, beta read for me (twice!) and taught me so much about writing. Thank you, OughtaKnowBetter! (If you want to read some truly fantastic work, check out her profile!)

This story is set a few weeks after the episode Sniper Zero in Season 1. However, it does feature Colby and Megan, because I think they're awesome...so please forgive this lapse of canon timing!

This story is complete and I will be posting a chapter every day until it's all up. This is my first Numb3rs story. If you want to leave a comment or review, I'd love to hear what you think!

Thank you for reading! I hope you enjoy it! :) ~Emily

11235813213455891442333776109871597

Fear. A blinding, crippling fear that sent his heart beating in triple-time and threatened to take over his mind.

His hands scrabbled senselessly over the black asphalt and shattered glass, his whole body trembling. Gunshots erupted, assaulting his ears. Someone had just tried to shoot him. Seven out of the eight sniper victims had died. Statistically speaking, he was dead.

The danger had just never seemed real. As he had pointed out to Larry so flippantly, he was more likely to be mauled to death by a bear than to be killed by a sniper. Yet he had failed to factor in that placing himself in an area where he had just mathematically predicted the sniper's next attack, pointing out his most likely location, and being the only person in the entire area not wearing a bullet-proof vest, significantly altered the odds in the sniper's favour. Stupid, stupid.

He saw the black muzzle of the rifle appear the window, exactly where he had predicted. Then Don's yell, the impact of David knocking him to the ground, the scream of the bullet as it ripped past his cheek and shattered the car window. He should be dead.

There was blood on the ground. Fear choked him. He pushed himself up, looked down. There was a gaping hole in his chest.

Charlie's eyes shot open. He gasped, pushing himself into a seated position, heart pounding, sweat dripping into his eyes, trembling. It was dark. He ripped open his shirt, stared down at his chest. No bullet hole, no blood.

He let out a long, shuddering breath and buried his head in his hands, pushing at his eyes as if his hands could literally wipe away the image. It seemed so real. Then he swung his feet to the concrete floor and made for the light switch. The garage sprang into illumination. His work on P vs NP covered the multitude of blackboards. He walked back over to one of the boards, pushed sweat-soaked curls back, picked up a piece of chalk. He'd just sat down for a minute…had not meant to fall asleep. The nightmare was always the same.

For the first few weeks he had thought he was fine. Even been proud of shaking it off so easily, getting shot at, all in a day's work for Don, so Charlie could handle it too, right?

Then the dreams had started. For the last three nights, several times a night, he relieved that moment of abject, paralyzing terror. The only difference was that in real life, the bullet had missed. But if Don hadn't shouted, if David hadn't moved exactly when he did…

Delayed shock, delayed reaction, the rational part of his mind tried to tell him. Unfortunately that part was not as strong as the primitive instinct screaming at him to run, to hide, to get away from the perceived threat that continued to prey on him.

He shook his head, raised his chalk to the blackboard, and began to fill his mind with numbers. Numbers left no room for emotion, no room for pain. Numbers were safe.

11235813213455891442333776109871597

"Charlie?" Alan Eppes stood at the door. There was no response from his youngest son. He was doing the same thing as he had when Alan had headed off to bed the night before – scribbling frantically at one of the many chalkboards hanging and leaning around the garage. Still dressed in yesterday's rumpled shirt and jeans, Charlie's face was pale and dark shadows ringed his eyes.

"Charlie," he repeated, raising his voice slightly. Years of experience had taught him that it was no good expecting Charlie to respond immediately when his head was buried in a problem. "Charlie…" he walked towards his son, concern growing on his face. Even for Charlie, this was unusually unresponsive. He touched Charlie's shoulder.

Charlie jumped violently, the chalk tracing a jagged line down the board as he spun around. Wide dark eyes met his father's face.

"Geez, dad, you startled me," Charlie gasped. He took a deep breath, tried to look back to the chalkboard. "I'm working…"

"Charlie, you've been working all night, and all yesterday," Alan interrupted, his voice rising. "You didn't even eat the sandwich Amita brought you. And you just about had a heart attack when I tried to talk to you. What is it that's so important?"

"Just let me…" he turned back to the board, already sinking into the problem.

"Charlie, listen when I am speaking to you. This is P vs NP, isn't it?" Alan recognized the work, though he could not follow it. The fact that Charlie was working on this particular problem again worried him. He knew through long experience that P vs NP held some special fascination for his son. Unfortunately, it was a fascination that could so easily tip over into obsessive-compulsive behaviour.

"Yes, and I am trying to follow through on an important expression, so if you would just let me finish…" Charlie rubbed out the scored line with his shirt sleeve and continued to write a string full of symbols and summations. Alan sighed. He couldn't reprimand his son the way he could when Charlie was a kid. No matter how much he wanted to snatch the chalk out of Charlie's hand and send him to his room, it just wasn't possible to do so when his youngest had become a twenty-eight year old, multiple-doctorate holding Professor.

"Why are you working on this again? You said you were going to focus on your cognitive emergence thing."

"Dad!" Charlie snapped. "I need to work on this, okay? I need to focus. I need quiet. Leave me alone."

Alan gave up. There was no speaking to Charlie when he got like this. Although…maybe there was something he could do - call Don. He knew Charlie had been doing some on-and-off consulting for the FBI, so maybe Don had some idea of what had tipped Charlie over the edge this time.

11235813213455891442333776109871597

"He is?" Don swore. Of course, he knew what had set his little brother off. By mutual agreement he and Charlie had decided not to tell their father how close Charlie had come to being the next statistic. It would just make Alan panic, they knew, and after all neither of them had been harmed and the shooter was dead. What Alan didn't know couldn't hurt him, right?

Don battled down a mixture of annoyance and concern. Why couldn't Charlie just behave normally? Hell, Don had been fired at more times than he could keep track of – even been winged a couple of times – and he didn't spiral into the mathematical version of panic attacks.

He pushed the unjust thoughts away. This was his kid brother, not an experienced agent trained to deal with the psychological effects of being shot at. He couldn't expect Charlie to behave like Don himself would. He kicked himself for not remembering that Charlie might not be able to shrug it off so easily.

"He'll be okay…look, I'll come over later and talk to him," Don promised his father. A beeping noise in his ear alerted him to another call. "Sorry, I got a call waiting. See ya later," he added, and switched to the incoming call. "Eppes?" His face went serious. "Okay…"

Two heads – one blond, one dark – looked up from files and forms. The tone of their boss's voice was enough to make Agents David Sinclair and Colby Granger pause in their work. Don snapped the phone closed.

"We got another shooting."

"What?" Colby couldn't believe it. "But we took that guy down! The copycat attacks were supposed to stop!"

"Looks like nobody told that to this guy." Don said grimly as the memory of the day they'd finally caught the serial sniper rose in his mind.

He's here somewhere.

Don scanned the windows of the tall office blocks surrounding the square. They'd cleared the area of civilians – the sniper wasn't gonna take another victim, not today, not on Don's watch. All they had to do was stop the guy from getting away. With teams in every alley and a chopper in the air, Don was confident that today was the day. Today they'd get this thing in the bag. No more shootings, no more deaths.

The sound of an engine drew his attention from the LAPD officer he was speaking to. He glanced around as a car door slammed.

No. No, no, no!

His heart seemed to freeze. Charlie couldn't be here, couldn't be wandering around the empty square predicting tangents and angles in his mind. Couldn't be taking down notes on exactly where the bullet that would kill him would come from.

"Charlie! Get down!" His voice was hoarse with horror. He shoved the officer out of the way. It was faster than he'd ever run in his life, but it felt like running through glue.

It wasn't enough.

BLAM.

Charlie was on the ground. Hit? Every gunshot death Don had ever seen flashed before his eyes. Charlie's face superimposed on each victim.

His thoughts were brought back to the present by David muttering something unprintable under his breath. Probably reliving the very same moment, Don realized. He shook his head, clearing the memory away.

This was unbelievable. After the Bureau had caught the perpetrator and closed the case, people were finally beginning to think the streets of L.A were as safe as they'd ever been. Now this had to happen. Don sighed. "Look, get down to the crime scene and check it out, ok? I'm sure it's just a leftover from the copycat virus thing but I'm gonna pick up Charlie on the way, see what he thinks."

11235813213455891442333776109871597

"Hey Charlie –"

"Can't you see I'm working-?" Charlie yanked headphones out of his ears and glared at his brother. Don blinked. Okay, so now he could see what Dad meant. It was unlike Charlie to greet you by biting your head off. He swallowed the stung retort that rose to his lips. Stay calm.

"Yeah, but I've hit a problem and I need your help," he said. It was a calculated remark. Charlie could never resist helping Don out.

Charlie crossed his arms and scowled at the chalkboard. Well, at least he wasn't scribbling strings of esoteric symbols any more. That was as good an invitation as any.

"There was just a sniper attack. Someone used a hunting rifle to shoot a man on the street from a nearby building." Don watched as the scowl dropped from Charlie's face, to be replaced with a look of horror. He could see the implications flashing through his brother's brilliant mind.

"You think it's another serial attack."

"That's what it looks like."

Charlie shook his head. "Another innocent person dead…" he wasn't speaking to Don. He looked at the ceiling as if the answer were written up there among the hanging chalkboards and cobwebs.

"I'm sure you caught the right guy, Don. The rash of copycats might take a while to fade out even though so many of the attackers have now been caught…people still have the hunting rifle idea implanted. It could even be an anomaly, not related to the previous attacks at all." Charlie was obviously trying to match Don's calm demeanour, but he couldn't fool Don. His brother was scared stiff.

Don tried to see it Charlie's way. "Look, I know it was scary back at the square but the crime scene has been secured and we really need to know if this shooting fits the serial killer's pattern. You know the killer never sticks around, you've been to the scenes before…there's no danger."

"I know," Charlie snapped, but the chalk in his clenched fist was beginning to crumble. Don looked at him, taking in the bruised-looking shadows under Charlie's eyes, the tension that radiated from his brother's wiry body, and started to rethink the idea. Charlie really didn't look so good. Don had thought that getting him out of the garage and into the real world would snap Charlie out of this state. Now Don was having second thoughts. Maybe it was better if Charlie didn't come, after all.

"Look - if you really don't want to come, I can get photos -"

"No." Don watched his brother take a steadying breath, visibly forcing himself to calm down. "Observation is an important tool in data analysis..." Charlie grabbed his jacket from the couch.

"Okay then." Don nodded and let the way out to the black SUV, pushing his sunglasses back over his eyes, masking the concern.

11235813213455891442333776109871597

Charlie's hands were shaking. He stared at them, willing them to stop. When they wouldn't he sat on them and gazed blindly out of the car window. This irrational fear was just ridiculous. Don needed him to help with this case. He shouldn't be such a coward.

The car pulled up and Don jumped out, Charlie hesitating just a moment too long before doing the same. As usual the perimeter was surrounded by yellow tape and Charlie followed Don as his brother flashed his badge at the LAPD officer before ducking under the security line. Charlie showed the officer his own ID, his eyes darting around the scene. Now that he was here, his earlier fears were beginning to recede. The reality of things was actually a lot less scary than his own imagination made them, and the details of the case were flowing through his mind, banishing the memory of the sniper shooting at him. The fear created by the mind can overwhelm rationality, he mused. Could that be expressed in an equation…?

Don had been right. Getting out of the garage was a good idea. Charlie studied the tape that outlined where the body had fallen, trying not to look too hard at the red-brown stain in the chest area. Then he turned, squinting into the sunlight, using the angle of the body placement and mentally calculating the ballistics and atmospheric conditions to determine the most likely location for the sniper. He glanced up to the resulting rooftop and spotted someone moving up there.

His heart jumped. Who….

Oh. Of course.

Agent Edgerton might not be a mathematician, but he sure did know how to pick a sniper's nest.

The pieces were falling into place. He turned to Don. "It's not a continuation of the serial trend. Despite the fact that the shot killed, it's actually a low skill level shooting. Remember what I showed you about regression to the mean? This attack is below the mean skill level of the serial sniper's attacks." He pointed out the rooftop location, a low empty building that was close to the street, with little activity in the area for the shooter to worry about. "The viral behaviour he started will take a while to fade out. If I graphed the attacks now, you'd see the upward curve level out along the y axis as attacks grow more infrequent."

Don nodded. "That's what we were hoping. Thanks, buddy," he said briefly and moved a few paces towards Megan, waving the rest of his team to come over.

Megan had a shadow today, a fresh-faced, dainty-looking girl whose flak vest and service piece were at odds with school-girlish bangs, barrettes and sparkly fingernails. Trainee Shelley Ramirez looked like she couldn't be more than sixteen, but Don knew that couldn't be true. Quantico didn't accept anyone under the age of twenty-three, for a start. To make it here to the LA office, Trainee Ramirez had already completed sixteen weeks of intensive training – including that which gave her the right to carry the Bureau-issued pistol on her belt - and if she held her own whilst shadowing an active team, she would graduate in a couple of weeks.

Don scowled. He'd managed to slide out of having trainees in the past, but the AD had finally caught on to him. He thought it must be the AD's idea of payback, giving him FBI-Barbie.

"No ID," Megan's face was glum. Behind her, Trainee Ramirez nodded agreement, her ponytail bobbing. "Nobody seems to know who he is. They're sending him to the County General morgue for autopsy."

Colby came up, holding a packet of something between gloved fingers.

"Check this out. This was on the guy."

"That what I think it is?"

"If you're thinking drugs, then yeah," Colby grimaced. "We'll get it processed and ID'd down at the lab, but my money's on Rainbow's End."

"Rainbow's End?"

"It's the street name for dextrodiphetamine," the trainee piped up. Don looked at her in surprise. "New trip of choice for over-privileged teens. Sells on the street for a hundred bucks a gram." She shrugged a little awkwardly at Don's questioning stare.

"She's right," Colby agreed. "It's just come on the market. Janssen's team have been working on it. Mike was telling me about it just the other day. Some drug lord holds the monopoly and is making a real killing, only they can't figure out which one."

"Okay," Don let it go for now. "Charlie says this one's not part of the serial trend, so let's look into the drug-related angle. Maybe we get to hand over to Janssen. Colby, get that down to the lab. Oh, and take Ramirez with you, since she knows so much about it." The trainee flushed, but followed Colby.

"Hey, be nice," Megan told him.

"What? –" A beeping from Don's pocket alerted him to an incoming call. He pulled out his cell and flipped it open. Megan sighed and headed back over to the security line.

Glancing around as he put his phone to his ear, Don spotted Charlie, still standing by the mark where the body had lain. His brother was staring blankly into space, completely zoned out. No doubt he's thinking of some crazy math problem, and having a lot more fun with it than I am with this damn case.

He focused back on the voice in his ear and scowled at the message the caller was giving him.

"I'll be right there." He snapped the phone closed and strode over to Charlie. "Hey, Chuck?" he watched Charlie's attention zone back in from whatever tangential plane it had been on. "There's another case where I'm needed. I get to leave my people here while I assess the new crime scene." He shoved his phone back into his pocket. "I wanted to drop you back home, but it's well out of the way-"

Charlie interrupted him. "It's okay Don, I can come with you. Maybe I can help," he offered.

Don frowned; he had been going to ask Colby or David to drive Charlie home. Then again, this particular case was already sounding like something Charlie could give a lot of insight to. And, he convinced himself, a new problem was likely just what Charlie needed.

"Okay. You're on," he nodded and led the way back to the SUV.

11235813213455891442333776109871597