- - - - -

Megan was hoping if Charlie didn't hear her she could watch him work a little while, but it only took him a few minutes to notice her there. She smiled. "Hey, Charlie. You sleep okay?"

"Yeah, I think I zonked out ten minutes in," he grinned, jotting a few things down then setting his marker down.

"So did Don drive you over?"

"Yeah, he's just getting-" The door suddenly swung open and Don came in. Charlie waved a hand at him. "Never mind."

Don looked up from the steaming cup in his hand. "What?"

Charlie shook his head. "I'm telling you, you shouldn't have made that coffee right before bed. You barely slept last night, don't think I didn't hear you get up like four times."

Don just shrugged and took a sip of his coffee. "So whatcha got?"

"Actually, it's coming along pretty well, I think- my head's a little clearer, you know."

"Heard from Dad yet this morning?" Charlie held up four fingers and Don raised his eyebrows. "Really?"

"Once to make sure I had clean clothes, once to ask me where you and I were eating lunch and twice just to 'check in' as he put it."

Megan grinned at them. "Alan's a caring father, you have to give him that."

"You know it would have been more poignant if the first call hadn't been at seven in the morning."

"That why you look so worn out?"

"No, working on this for the last four hours, that's why I'm- I'm starting to glaze again. Although, I think I may have a umn…I might be getting somewhere."

"Uh-huh." Don nodded. "Good, well…don't let me keep ya."

Megan and Don left, talking quietly about a forensics report, and Charlie went at the board like it was a lifeline. Maybe it was.

Actions 82.151

Location 66.243

Business 68.832

Personal 77.273

A half-hour later, he stopped, marker frozen over the glossy white surface. His heart pounded in his ears. He stepped back, surveying his work, but the same conclusion kept resurfacing over and over. Hesitantly, he set the marker down, cleared his throat, and left to find Don.

- - - - -

Don counted heads briefly. "All right, we're all here Charlie, what's up?"

"I may know how to find our suspect."

Megan took a seat. "Is it a point-to-the-map result or more of an 'imagine a game of hide-and-seek' kind of thing?"

"That's just it," Charlie said, pacing in front of the whiteboard, knuckle to is mouth in thought. "It's not a target at all. There are…simply too many factors."

"Just work off what you know, Charlie," Don told him. "Like what that lecture you were giving was on. I mean, that could have something to do with this, right? Your Ramsey Theory…you know, computer password thing?"

Charlie scuffed his feet against the floor like an edgy colt. "Yeah, sure it could. So could the other twelve lectures I've given over the past couple months, or the classes I've held in the last week, or-"

"Woah, wait." Don cut in calmly. "You mean to tell me you can sift through, what, like a million factors for each of our suspects, but you can't work the math for your own analysis?"

"I'm analyzing myself, Don."

"Yeah, I know. So there's no guesswork."

Charlie seemed agitated. "No that's just it, it's enormously more complex with personal considerations thrown in. I've crunched the numbers, I have calculated probability from each angle I can, it's over 50 likely in each direction." He fell silent for a moment. When he spoke again, his voice was barely audible. "I can't figure out who's trying to kill me. I just- it'll take too long, there's too many options."

"Well…" David glanced around. "We can give you as much time as you need, Charlie-"

"It's not- it's not that, David, thank you." He leaned against the wall beside the whiteboard, trying not to snap. Don didn't like the way this was beginning to feel.

"Charlie? What's…what's goin' on, what're you thinking?"

"Don," Charlie's voice cracked a little. "I need to uh…if I settle into a routine again, if I- make everyone believe that we think Jim Blake's our guy, then whoever we're after will come to us."

Don just stared at him, fear backed by determination glinting in his face. "Now wait a second, Charlie."

"I ran the risk and security factors on my locations, CalSci has the highest for both."

"Charlie-"

"We'd have familiarity, access and surprise on our side, that's you know, gotta count for-"

"Hey- stop, all right?" Charlie's words stumbled to a halt. "I'm not using you as live bait, kay buddy? It's not an option."

"Why not."

Don sputtered impatiently. "I can't- I can't even begin to list the reasons why not, Charlie."

"It's the only alternative-" Don was shaking his head vehemently which seemed to irritate his brother. "I've run the numbers over and over, I can't figure this out!"

"Don't give me that, you can figure anything out with your numbers."

Charlie sank, defeated, into a chair and folded his hands in his lap. "Not this time. My uh- my expertise has finally met its match, I think." He looked up. "I gotta do this."

"Charlie." Don raised his eyebrows indicating it was a closed issue. "It's not gonna happen."

Charlie gritted his teeth. "Why can't you-"

"Charlie," Megan broke in, kneeling beside his chair. "Don's right. Okay, and I know you think this is the only way you're going to make this go away, but…we can't put your life on the line to save it. What good would that do, right?"

"And what's going to happen if you don't," He asked, jaw clenched. "Am I going to go to some shack in San Marcos till we somehow find this guy? And Dad," he looked up a Don. "You gonna send him to? And Larry and Amita- Don, it doesn't stop. You're not even safe so long as we have no idea why these people are after me. It's not just my life we're dealing with here."

"Well you're the only one they've come after, so you're the one I'm worrying about for now, Charlie."

"So far." Don just looked at him then looked away. The room fell silent for awhile, the lack of options making the air tense. Charlie stood up slowly, and went to stand behind Don.

"Listen," he said. "I wish I could figure this out, but I c…I can't. I'm the only one who can run this personal analyses accurately, and I can't- see the numbers, the connections…" he forced a light laugh. "I can barely see straight lately. Don?"

Don didn't turn around. "I gotta…I need to think. I'll umn…I just have to think." He left the room, and the four of them stood about awkwardly. Then Charlie gathered up his computer and slipped out of the room as well.

Colby was the first to break the silence. "You really think this is our only choice, or do you think Charlie's just not being rational anymore."

David just shook his head. Megan glanced up at them, at the chair Charlie had been sitting in, then at the door. "I'll go talk to Don."

Colby stood up. "I'll take Charlie some coffee, maybe it'll clear his head a little."

"Yeah." Megan stood. "Think someone should call Alan?"

David sighed. "I think…one shell-shocked family member at a time."

- - - - -

"Mind if I come in?"

Don, who's forehead had been resting on his palms, looked up. "Sure," he said noncommittally. Megan slipped inside, shutting the door behind her. She sat down and waited for him to open the conversation, but he seemed completely lost in thought.

"You know, Don…" she said gently, "this must be like a nightmare for you and your father, but…I've got to say, you've really handled it well. Both of you."

"Yeah?" He rubbed his eyes tiredly. "Well, you know. The Eppes family always had this unwritten rule. When things get ugliest, you put on a brave face for Charlie. Dad does it, Mom did it…I'm sort of a pro at it now." He laughed humorously, running a hand over his hair. "Ah man…you wanna know the truth, Megan? Not a minute goes by I don't want to panic. You know, when I think about…some guy's out there just waiting to take pot shots at my brother. And why? I mean- the guy's a mathematician. It's precisely why I didn't want him working with the FBI in the first place."

Megan chewed her lip, letting his thoughts settle. "What're you going to do?"

He opened his mouth to speak, shut it, took a long, steady breath, and sat up straight. "I can't even imagine what Dad'll say if I let Charlie go through with this."

"But- if it's the only option…"

"It's not, I could…I could put him in Witness Protection. We could just try to solve this thing without him."

"I sort of got the impression- Charlie didn't like that idea. I mean, why else would you send WITSEC back to base without him? Especially now Ken and Kyle are back on the streets."

"Yeah, well that's the thing, isn't it. I either push him in front of an almost certain attempt on his life, or I force him to go away for what could be weeks, even months since we won't have his help and he doesn't want to get Larry and Amita involved."

"Either way we end up scarring him." She shook her head. "So I guess-"

"Just looking for the lesser of two evils now," he finished, nodding.

Megan began to reply but the door suddenly swung open and Colby came inside. "Don, it's Charlie."

- - - - -

"Let go!"

"Charlie, just-"

"David, let go-"

"Look I'm just asking you to think this over."

Don came in to find Charlie and David in what looked like a tug-a-war over Charlie's backpack. "Hey, hey what's going on here?"

"David's-"

"I'm trying to keep him from running down to the firing range!" David insisted, letting go and sending Charlie flying back several steps.

He righted himself, zipping the bag shut. "I could use the practice if I'm going to take a piece with me."

Don reached in a snatched the backpack out of Charlie's hands. "With you where?"

"I'm going to CalSci."

Don groaned into his hands. "Charlie…"

Charlie's came spilling out like he couldn't inhale till he'd said them all. "Don't Don, it's my choice. And you can't force me to stay here or go into hiding. I'm not a kid, this is my choice. It's my life, I can put it on the line if I wan to, so either I'm returning to campus with the FBI behind me or without." He paused, panting. "And all things being equal, I'd really like to have you guys there."

Don stared at his brother for a long time, and Charlie stared right back, trying for all the world to appear in control. But Don could see beyond the façade of unabashed determination and it made his chest ache. Suddenly, he stretched out his arm and returned Charlie's backpack to him. "All right."

"All-" Charlie's eyebrows raised. "All right? You're agreeing?"

"Well you're not giving me much of a choice, Charlie," Don said resignedly. "When are you next expected at CalSci."

"Uh…" He checked his watch. "I've actually got a class this afternoon that I…tentatively left open."

"You're not gonna want to put your students in the middle of this," Don said, and Charlie shook his head vehemently. "So let's come up with a good reason why you can't do the class, we'll send you to campus this afternoon." He sighed heavily and clapped Charlie on the shoulder. "Okay, let's go get you set up. And you are not taking a gun with you."

"Uh Don…what about Dad?"

"One thing at a time, kay?"

- - - - -

"How you doing, Charlie?"

Charlie jumped and put a finger to his earpiece. "Yeah, uh…fine."

"Okay," Colby said patiently on the other end. "You need to stop reacting when I talk to you."

Charlie dropped his hand. "Sorry. Did Megan get a hold of Larry and Amita?"

"They're going to steer clear from you for the afternoon. We'll just see how this goes. Remember, stick to as many vacant places as you can." Charlie nodded, hesitating as he reached the library doors. "What's up?"

"Does umn…is Don there yet?"

In the van, parked beyond the bushes just outside CalSci's gates, Colby glanced at Megan. "Not yet. Hang in there, okay? He'll be in position any-"

"Right here, buddy." Charlie relaxed as Don's voice came through his earpiece.

"Hey, you."

Don smiled. "Hey. You at the library yet?"

"Yeah, can you not see me?"

"Not yet, I'm out back. You're gonna go through the library and out into this grassy spot back here."

"You mean the garden?"

"Is it? Okay, sure."

Charlie glanced around cautiously, still stationary. This was his idea. He should be pursuing it whole-heartedly, not freaking out every step of the way. But he couldn't make his hands stop shaking. "This guy's MO, it's bombs, right?"

"Yes it is," Megan's voice answered. Charlie ducked his head, nodding and trying to pull himself together. "It's okay, Charlie. We didn't give him enough time to plant a bomb, he's either going to have to change his MO or risk not having you out in the open like this again."

"So we're gambling."

Don answered him after a moment of static. "If anyone can beat the odds, it's you. Just remember the key phrase."

"'Where did I put my seminar notes'," Charlie recited.

"Just say the words and we'll move in." Charlie took a deep breath, put his weight behind the library door and slipped inside.

"Okay, I'm halfway through," Charlie whispered, trying to get his knees to stop trembling. "Should I-"

"Professor Eppes!" Charlie spun around to see a young man tearing up the hallway after him.

Don sounded anxious. "Charlie what's going on?"

"Adrian," Charlie greeted him, trying to smile. "What can I do for you?"

"You said that you'd help me with my theorem?"

Charlie put his hand to his forehead, flustered. "Oh. Right- yeah, sorry. Umn…listen, now's a really bad time, Adrian."

"Oh please, Professor, just a few minutes? This is counting towards my grade, I mean- this is like 20."

"You have always received good grades, I don't know why you're so concerned."

Adrian twisted the rim of his jacket. "But Professor St. James says that most of the grading is based upon style." He winced. "Please, just ten minutes?"

Charlie's ear vibrated with Don's voice. "Don't, Charlie, you don't want to get your students tangled up in this."

Charlie smiled pleasantly. "Tell you what. Why don't you meet me in my office later this afternoon-"

"I have to finish this before tomorrow morning," Adrian pleaded. "If you can just help me with this one point, I'll be able to write the theorem tonight. I'll work till three if I have to, but I am determined to score well on this test."

Charlie bit his lip, glancing around. "Ten minutes."

Don switched Charlie's line off, calling to the van. "Megan, get me anything you can find on this Adrian kid, just in case."

"There are…" he heard keys clicking. "There are two Adrian's at CalSci."

He hit Charlie's switch again. "Charlie, we need Adrian's last name."

"This way then, Mr. Culla," Charlie said nonchalantly on the other end.

"Megan?"

"Searching now…"

"Can we go down to the Senior's lab?" Adrian asked, glowing with relief. "It's empty right now and I could test my theorem."

Charlie paused in supposed consideration, waiting for Don's feedback. Finally, Don came through on the com. "Okay, that's just across from the library, I'll move around so I can keep an eye on you."

"All right, that should be fine. But just ten minutes or so."

"Thank you Professor Eppes, you won't regret this."

Charlie led Adrian down the hall and out the side door, summarizing the difference between theorems and corollaries in the most basic terms he could. Don could hear the strain under his voice all the while. He hoped Adrian missed it. Colby grabbed the binoculars and watched as the two of them crossed the long sidewalk and ducked inside a different brick building. "Don, he's inside."

"Copy. Moving positions now."

"You know," Charlie said as they climbed the stairs. "We're coming up on Professor Fontana's office."

"He's currently working on his theory of magnetic control," Adrian replied. "He was telling some of us about it the other day."

"Did you know that the model he's working on is so strong that it's been blowing out his electronics? He told me he can't even keep his computer in the office right now." Charlie shot Adrian an amused look. Don caught the tip.

"I hear you, buddy," he told him. "You guys, we're going to lose contact with Charlie for a minute here."

"Got it," Colby answered back. And sure enough, seconds later, there was nothing but static.

Don waited five solid minutes without a word. Then he couldn't wait anymore. "Charlie, you there?" The static continued. "Charlie, if you hear me clear your throat." Still nothing.

"Maybe the magnets blew out his earpiece," Megan suggested.

"No he'd have told us if that was gonna happen. Charlie? Charlie, do you copy me?"

- - - - -

Charlie's pulse quickened as the static continued long after they'd left Professor Fontana's office door behind them. He attempted to keep his cool as he and Adrian finally entered the Senior's lab. He needed to fix the problem, get out, and get a hold of Don.

"So what exactly seems to be the problem?" he asked, seating himself uneasily in a chair by one of the many steal tables that decorated the lab.

"Well," Adrian said quickly, "we have to have a logical, working theorem, correct? And it's meant to be unspecific, uncategorized. And yet…I think I've created a corollary."

"You know all this would probably be simpler, Adrian, if you could show me your theorem?"

Adrian blushed. "Oh, right, sorry." He pulled out his bag and dug around inside for several moments. "I know…I had it…"

"You need some help?" Charlie began to rise, but suddenly stopped. Adrian had found it what he was looking for.

"No thanks. Please have a seat, Professor."

Charlie sat slowly in his chair again. His heart pounded like thunder in his ears, his chest, his very fingers vibrated. And his eyes couldn't seem to leave the small, silver handgun that was aimed directly at him. He tried to swallow the lump in his throat. "Adrian-"

"Shh…" Adrian shook his head. "It's my turn to talk this time."

- - - - -