- - - - -

Don paced restlessly in front of the whiteboard. The whole briefing room was silent as everyone sat in thought. Finally he pointed to three pictures on the board and said, "Ken Dryger, Jim Blake and Kyle Ross. So we've been interrogating these guys for two days and we're still getting cocky remarks, smart-alecky answers and absolutely no actionable clues. Is that code we found on Blake back from Deciphering yet?"

Megan shook her head. "Due to our analyses of this gang thus far, I've advised they narrow the search to sophisticated coding. They're thinking it may be Huffman coding, but without a key, they're having to do it trial-and-error."

"Any ETA?"

"Five days, maybe a week."

"The longer we have these guys and no answers, the greater the risk of another bombing."

Megan nodded her agreement. "Don's right, without knowing more about this gang itself, there's no predicting the repercussions."

"We could try different tactics," David said, taking a second look at the suspects' files. "All three of these young men are smart, promising before they took up petty crimes. Maybe we could get some of their families in here."

"The forms would take too long, and we can only hold them so long on suspicion charges. We're running out of time. Plus their parents and their lawyers, I'm sure, are all ready knocking down the door to peruse legal action. I'd rather not invite them in."

Megan pushed her hair out of her face, sighing. "And that's another bizarre thing that's getting to me. I had to call the parents myself. None of the boys showed any interest in contacting their families, schools or lawyers."

"Embarrassed?" David offered.

"Possible." But she sounded unconvinced.

"We're getting nowhere with any of them," Don said firmly.

"So…" David glanced around. "You're suggesting what?"

He thought a moment, then looked up. "I'm taking that code to Charlie."

- - - - -

Charlie ran a hand over his face, laughing.

Larry, still trying to keep his own voice steady, continued, "So- so I said, you know, 'uh…Chris, where's the g?' and he says, 'what do you mean, professor?' and I told him, 'if the F is the prefix to the equation, it stands for 'force', but it's not just force, it's gravitational force' and he says, 'is that what the F was for?'" Charlie thumped the table, still laughing. "And I said, 'well Chris, what did you think F stood for?' and he says, 'well you put it there, shouldn't it stand for Fleinhardt?'"

Charlie, once he'd stopped laughing, patted Larry on the shoulder. "My condolences, professor."

"Yes, well," Larry sighed, wiping his eyes. "Just one of the myriad of joys that comes from being a teacher."

Charlie grinned. "The opportunity to laugh at the naiveté of one's students?"

Larry laughed again, shaking his head. "Exactly," he said at last, running his hands over his face. "Ah…to be young and incoherent."

"Well I envy you, I'm currently feeling guilty for my students. Grant, Adrian and Trey are all home with the same fever I just got over."

"You didn't come to classes till you'd fully recovered, so you can't blame yourself for that."

"Yeah," Charlie stood up, fiddling absently with a piece of chalk. "Hopefully things will be back to normal by tomorrow."

Suddenly, the door opened and Don strode in. "Charlie, hey."

Larry looked at the ceiling, "If your life is ever normal, Yoichiro Nambu was color-blind, Charles…"

Don glanced at him. "What?"

Charlie shook his head. "Ignore him, he's just suffering from the idiocy of his students-"

"Idiocy implies the incapability to register knowledge, Christopher Ricks is really more of an obdurate adolescent. I think I should take up farming, I hear goats are far less stubborn than undergrads."

Charlie smiled brightly, and went over to Don. "So what's up? How's it coming with the museum guys."

"Ah, not too great."

"Oh yeah?"

"Yeah, I mean it's all glib comebacks, nothing substantial."

"Well you know, arrogance is often the first sign of insecurity."

"Yeah, but we're getting nothing. I don't think these guys are afraid or overconfident, they're just…" he shrugged. "They're just confident."

"So what do you need me to do."

"Well, we got this note off one of them, and it's in code. We sent it down to Deciphering, but I…could really use your help on it."

"Yeah, sure you bet."

"I made you a copy…" Don reached into his coat and pulled out a small, yellow envelope marked "confidential" and handed to his brother. Charlie flipped it open, eyes scanning down a page with nothing but 1's and 0's from the top to the bottom. He slowly began to nod his head.

"Binary…Huffman, maybe, it looks a little like a branch format. And it's a repeating design. One, two…seven times." He looked up and found an amused light in Don's eyes. "Well, I'm guessing your guys all ready figured that out."

"Yeah, but…took 'um two days."

Charlie grinned a little, and looked back at the page. "I swear I've seen this before. I'll need to take a closer look at the structure, maybe run it through a program."

Don held his hands up. "Whatever you need. Look, if you could just generate a key for me, that'd be great."

"You don't want me to decode it?"

Don shrugged, a little uncomfortable. "Charlie, I'm trying to keep you on need-to-know basis, I don't like getting you tangled too deep into this stuff."

Charlie was all ready nodding, "Right, sorry. I'll put together a key."

"Thanks buddy, you're the man." Charlie just smiled and watched him go. Then he put the page on his desk and started pounding away at the chalkboard.

Larry watched him a little while. "I guess I'll leave you to your work, Professor FBI." After receiving no response, he just got up and headed to the door. Charlie turned around suddenly.

"Larry. This could save lives."

"Almost certainly. But you know what they say about heroes." Charlie shrugged, and Larry gave him raised eyebrows. "They sometimes fall."

- - - - -

"All right, thank you…thank you for your time, sir." Megan hang up the phone with an exasperated sigh.

Don glanced up from a pile of crime scene reports. "What'd they say?"

"The request to restrict visitation and outdoor activities has been granted. After pulling most of their teeth, they're going to keep Greer and Pullman on lockdown till we get this case sorted out."

"Good." Don looked down again.

"So…you took the note to Charlie?"

"Uh…uh-huh, yeah." Don seemed distracted. Megan leaned over, snapping her fingers a few inches under his nose. He looked at her, confused.

"What's up with you?"

He shook his head. "Nothing."

"C'mon, something's been bothering you ever since you got back from talking to Charlie this morning."

Don sighed. "It's been three days since the bomb at CalSci, Charlie's only just now felt comfortable enough to go back there. And then I come in, asking for his help on the case again."

"Well…two days isn't exactly hibernation, Don." Megan shrugged, smiling. "If you ask me, he bounced back really well this time."

"Yeah, no you're right, he did. I just usually like to lay off him after something like that, but I…you know, we need him on this case."

"Yeah we do. And he's happy to help." She patted his arm, sitting down in front of her computer again. "Don't worry about him so much."

Don rubbed his forehead, laughing lightly. "It's my job."

As if on cue, the door swung open and Charlie came running in, David and Colby in-toe. "Don! Hey, Don, good news."

Don straitened up. "Did you break the code?"

"Yes. But don't go saluting me yet, the thing is," he pulled out his laptop, setting it on the desk and opening the lid, pausing dramatically. "It just, plain wasn't very complicated. Do you know what the most-used vowel in the English alphabet is?"

David shrugged. "A?"

"Close, it's actually E. But, to break a code like this we usually start with the letter A and its component then go to B, C, D and onward. See, Huffman's coding is binary, but it's complicated, it works off an entropy encoding algorithm, which means it's progressive. You have to start at the beginning and work your way down."

"Right, okay," Don nodded, clearly catching none of this. "So what was that about E?"

"Well, I discovered the likely properties of A, B and C. Then I realized I was getting excess notations. There just wasn't enough variety in the three-digit sets, this note would have to either contain only eight or nine different characters, or…" He flipped the laptop around. "It's ASCII."

Don leaned over quickly. "What?"

"Yeah, it's basic substitution binary language. You don't need a key, you can get something like this online."

"But that's so- easy," David said, bewildered. "Why would they bother with a code a high school student could crack?"

"If you think about it, it does fit the profile," Megan pointed out. "Gangs, even meticulous ones, are typically thrill-seekers. The whole coded message thing is probably more of a James Bond complex than an actual strategy."

Don was nodding, wheels turning. "Okay. Okay, Charlie, let's send your analyses downstairs, let them double-check it. That okay with you?" Charlie shrugged his assent. "Okay, the minute that message is decoded, I want everyone in this room. If it's a name, an address, anything, I want to be ready to move on it."

The room cleared quickly, and Don gave Charlie's shoulder a squeeze. "Good work, thanks."

"Well I don't know that I did much, but…" he handed the yellow folder to Don, and smiled. "Any time." There was a pregnant pause. "Listen, I uh…I noticed you didn't call me after the museum bust. I had to call Megan and ask what happened-"

"Hey, I don't give you to-the-minute updates."

"Yeah but you said you'd come by with those statements-"

"I got busy, Charlie, you know how it is."

"No, I know, but it's just…" Charlie looked a little uncomfortable. "You don't have to cut me out of this. You know, just because CalSci was somehow involved doesn't mean…you know. I'm fine. I really am."

"I know that." Don said sincerely, nodding for emphasis. "I know. Look, I understand you've got a personal investment in this now, and I respect that. I don't want you getting caught up in this just because of the CalSci bombing, but I'll tell you this: If there is anything I feel you could do to help me, I won't hesitate to let you know."

That seemed to make him feel better. "Okay. Thanks." He walked to the door, a spring in his step, then turned, "Oh, and if you were thinking of coming home this evening…don't know I'd recommend it."

"Yeah?"

"Dad's making that macaroni pasta he used to make for Thanksgiving."

Don gagged. "The stuff that made us sick?"

"Well he says that we were sick before we ate the pasta, but yeah." Charlie smirked. "Want me to uh…tell him you caught the bug I got and can't come?"

"Do you suppose if I got the bug while I was there I could blame it on the pasta?"

Charlie bounced his head back and forth, thinking, then shook his head, "Doubt it."

"Aw, c'mon. What are the odds of getting sick after the same pasta twice? Dad can't beat those odds."

"Well since you've had the pasta more than twice, you've got an average of 20-"

"Hey, hey- I wasn't talking about you, I know you can do it." Charlie, grinning, closed the glass door behind him.

Don watched him go, and was looking up some protocol information on the Los Angeles state prison when his phone went off. He pulled it from his belt. "Eppes."

"Agent Eppes, it's Bob Dorian in Deciphering."

"Hey Bob, how's it coming? How'd Charlie's key work out?"

"It's flawless, translated perfectly."

Don blinked, surprised. "You- you translated it?"

"Just a few minutes ago. It's not a long message, I'm afraid. Repeating pattern. You said to let you know-"

"No, yeah definitely. Can you send it up right away?" There was an odd pause. "Bob?"

"You may want to come take a look yourself, Don."

- - - - -

Don's footsteps pounded down the iron stairs. He showed his badge to the guard at the bottom and quickly pressed inside the double doors marked "Department of Encryption and Deciphering". A middle-aged man with sandy hair and a white lab coat came running up to him. "Agent Eppes? Bob Dorian."

"Hey, Bob. Where's the sheet?"

"Look umn…" Bob rubbed his hands together restlessly. "Let's go to my office." Don felt his irritation rising as they snaked their way between desks and computers. Finally, they reached the office and Bob ushered him inside, sliding the door shut behind him.

"What is it?" Don insisted.

"Look, I don't want to get you all worried for nothing. It's not conclusive, but it's…I just thought you should see it first." He handed Don a folder marked "DED Confidential". Don flipped it open, eyes sweeping over the page on the top of the stack.

His head came up slowly. "This is it? This is…this is all it said?" Bob just watched him, the question being almost rhetorical. "That's uh…that's…" Don shook his head and took a deep breath. "All right, thanks…thanks, Bob. I'll let you know if we find anymore, kay?"

"Send 'um on down." Bob gave him a polite smile he was too distracted to return.

He walked out the office door, the words on the page before him burning into his retinas: CHARLES EDWARD EPPES.

- - - - -

The room was silent as everybody seemed to be waiting for Don to speak up first, but he didn't. After he'd copied the decoded message onto the whiteboard, he had paced to the window, arms crossed, waiting for an explanation to come to him.

Eventually, Colby spoke. "Don…like they said, it's not conclusive. Greer or Pullman, whichever left this note for Blake, they're probably referring to the CalSci bomb. It's old news."

"Yeah," Megan put in, "the good thing is we now have a key, so if there are any more notes left for these boys, we'll be able to read them. Without that communicative option, we've got 'um."

"Not yet," said Don, sighing in a way that indicated he was pulling himself together. "Okay. So we only have those boys for another…maybe a few more days till their parents take legal action and get them out of our custody. So we press them as hard as we can."

"Play up the fact that they're not in communication with their head guy," added David, "that we can read their code."

"I don't know if that's going to come to much of a shock to them," Megan said. "If they really wanted to hide the messages from us, they shouldn't have chosen ACII."

"But we weren't supposed to find that note, right?"

Don pointed to him. "Exactly. I'll do Jim Blake."

Megan raised her hand. "I'll take Kyle."

"David, Ken Dryger?" David nodded. Don looked up at the whiteboard, hands stuffed in his pockets. "I wanna know why that piece of paper has Charlie's name on it."

- - - - -