Disclaimer: NUMB3RS and its associated characters, etc., belong to the show's creators and to CBS, wonderful people whom I have never met and have no connection to. I hope they don't mind me using them here; no legal infringement intended.

Author's note: I am delighted to say that at least one person is hot on the trail of finding the musical message - I'm delighted to say that there is actually someone trying! And she has picked up on some clues I hid in Chapter 4 - hurray! Sorry for the delay with this chapter. I'm having a bout of 'writer's malaise' and had to kind of churn it out. Please don't forget to review when you're done; I'm needing the encouragement lately.

This chapter features some Don-Margaret warm fuzzy memories that get a little cheesy. You have been warned.

BTW: in case you're wondering, we see the piano hanging out in the background of the Eppes' living room in more than one episode - I first noticed it in "Prime Suspect".

Unfortunately this chapter has not been as thoroughly beta-read as I haven't given my betas enough time to get back to me before I post this, but I'm going out of town for the weekend and wanted to get this up, as it's been almost a month (criminal, I know).

UPDATE JUNE 29/06: This chapter/story was written before the episode aired in which we learn about Margaret being a pianist and teaching the boys. WHO CALLED IT? Booyah.

Pitch Perfect - Chapter 5

by Deichtine

Andrea helped Charlie position the microphone over the music box's mechanism, and showed him through the various features of the recording program. She had been delighted and mystified when Charlie explained the music box and how it had mysteriously come into and hijacked his life. She seemed thrilled by the mystery, and her initial reluctance to allow a personal project from someone outside the department to use her lab resources had evaporated. Her own experiment paused for the moment, she sat quietly and listened as Charlie played the box into the computer program, watching the rise and fall of the waveforms as they appeared on the screen.

"Wow, that's..." Andrea searched for a word, then shrugged. "...Really weird."

"Yeah," Charlie said, with a close-lipped smile and a raise of his eyebrows. "You're telling me."

'So you think there's a message encoded in there?"

"The more I listen to it, the more certain I am that there is. For example, listen to this part near the end..." he moved the cursor back to the appropriate point and played it back. "There's a definite pattern there - one note, then two notes together, and it repeats on different pitches - bah bum bum, bah bum bum."

Andrea thought for a moment. "Would it make it easier if you could see the notation?"

Charlie nodded. "Actually, that's my next step - find someone familiar enough with music to write it out for me. Which should be interesting, given that we don't have a music department."

Andrea gently elbowed Charlie over to take control of the computer. "Never mind that." She clicked on various menus, entered values in certain pop-up windows, and hit 'Enter'. Suddenly the screen filled with musical notes, neatly printed in the treble clef. "You might have to double check it, especially the timing, but that should save you some time."

Charlie grinned. "Thanks! I had no idea we could do that."

Andrea shrugged and smiled. "This audio program was initially designed more for musicians recording their work than for linguists, but it turns out our needs are not that different. I seldom have any reason to use that feature, but it's come in handy a few times, with tonal languages. For really complicated chords and instruments with a lot of reverberation that feature actually doesn't work that well, but your music box produces near-pure tones, so it's fairly simple."

Charlie stared at the music, the pattern he had noticed even more apparent when viewed on the stave. He was fascinated. "Can we print this off?"

Andrea was already working. "Done. I'm also saving the music and the waveforms and the rest to image files for you. What's your email?" Charlie gave it to her, and leaned back to think about what he'd seen. So far the spectrographs and waveforms hadn't immediately 'spoken to him'; meaningful patterns had not jumped out at him shouting "here I am", but he was more hopeful, now that he had something concrete to work with.

Andrea closed down the program, and Charlie extricated the music box from the recording equipment surrounding it, then stood up to go, a little regretfully.

"Thank you again, Dr. Gajewski, you've been a huge help."

She grinned, and tucked a stray lock of hair behind her ear. "It's Andrea. Are you ready to do some speaking for me?" She asked, indicating her computer at the front of the room.

Charlie blinked. Speaking? Then he remembered the deal - in return for the use of the equipment, he had to be a vocal guinea pig for Andrea. He moved over to the other computer, where everything was all set up.

The artificial palate she'd been using when he first arrived was sitting on the table near the keyboard, and he regarded it a bit uncomfortably. What had he gotten himself into?

She saw where he was looking, and laughed aloud, a gentle, genuine laugh. "You don't have to use anything like that, don't worry. We don't want to scare you off on your first day." She picked up the palate and began coiling its wires. "Besides, you need to have them custom made, and they're pretty expensive. What I need today requires nothing more than a man and a microphone."

Charlie grinned. "Well, looks like you've got both right here."

Don tugged at his tie and straightened his suit, and absently tried to smooth away with his hand the wrinkles that had set in during his forty-minute commute. Beside him on the stylish leather reception-area couch, Terry was reviewing her notes from the last time they had questioned Ray Chrissom. Across the room, on the far wall, the word "Globecorp" was spelled out in large polished brass letters.

"Agent Eppes?" the receptionist called. "Mr. Chrissom can see you now."

Don and Terry rose as one, and entered the Executive Vice President's inner sanctum.

Chrissom's office was warmly decorated, with rich, polished woods and tasteful knickknacks and objets d'art - antiques, no doubt - strategically placed for maximum effect. Sunlight streamed in from windows set into two walls, and a water cooler quietly burbled in one corner.

"Mr. Chrissom." Handshakes all around.

"Agent Eppes, a pleasure to see you again. And this is...?"

"Special Agent Terry Lake, my partner."

"Enchanté. Agent Eppes, is it too much to hope that you come bearing news that our corporation has been cleared of any wrongdoing?"

Don shook his head. Chrissom was the kind of polite, outgoing, buddy-buddy businessman that set Don's teeth on edge. In some ways he almost preferred the gang leaders, robbers, terrorists and murderers he dealt with on the streets - at least they were honest about their dishonesty, and there was no need to maintain polite fictions.

"I'm sorry, but I'm afraid we have a few more questions."

Chrissom sat down behind his desk and leaned back into the high-backed chair. "Frankly, Agent, I don't know if there's anything more I can tell you. I'm a very busy man - "

"Yes, and we appreciate your cooperation on this very serious matter," Don interrupted, and retrieved a notepad from his inside breast pocket. "Now, the last time we spoke, two weeks ago, we talked about Globecorp's financial records. This time, I'm afraid the matter is more - " he stopped, looking for the right word.

"Grave," Terry supplied.

Don nodded. The perfect word. He set the notepad down, and opened the file he had brought in with him. "Marcus Sudre and Frank Rice," Don said, tossing the crime scene photos onto the desk before Chrissom.

For just the tiniest fragment of a second, Don thought he caught a flicker of genuine reaction on the man's face - a darkening of the eyes, a tightening of the lips, an added tension in the jaw; what it meant, he couldn't say. It was replaced almost immediately by a mask of sorrowful regret, an expression calculated to blandly say, What a pity.

"What a shame," Chrissom said, glancing at the photos, then turning his eyes away with proper decency. "Such a waste," he added. "They were bright young men, and would have gone far with this company. I certainly hope you're able to find the people who did this. Do you have any leads?"

"We're following up on some tips," Don answered non-committally. "How well did you know the victims, Mr. Chrissom?"

"Frank Rice I barely knew at all. He worked in a different area - I think John Fa's office. But Marcus..." Chrissom's eyes grew shadowed again, and this time Don was almost inclined to believe there was an element of sincerity hiding there. "...Marcus worked with me. Now there was a man who was going places. Hard worker, real eye for detail, killer instincts when it came to investments."

"What exactly did Mr. Sudre do for you?"

"He was an investment consultant, worked wtih some of our best clients. He's going to be very difficult to replace; he had built up rapports with the clients, and they trusted him."

"Mr. Chrissom," Terry broke in, "did Marcus have any enemies? Dissatisfied clients, maybe?"

"Rivals within the office?" Don added.

Chrissom shook his head no. "No, I can't think of anyone. What you need to understand is that Marcus had a reputation for honesty, for integrity. He had this old-fashioned sense of personal honour; he was sincere almost to a fault. Everyone loved him, everyone respected him."

Terry seized on this. "To a fault - do you think this sincerity was part of what got him killed?"

Chrissom blinked. "I really couldn't say. I guess if he told the wrong truth about the wrong people - but I'm afraid you're talking to the wrong guy about that." He shifted in his chair, checked his watch.

"Were you ever aware of Marcus being troubled by his work here? Did he ever confide in you?" Don asked.

"Not really. I was his superior, and, though we got along well enough, we weren't personally close. Now, Agent Eppes, I'm afraid I have a conference call in five minutes that I really need to prepare for." He stood up, and Don and Terry followed suit.

"One last question, Mr. Chrissom," Don said. "You understand I have to ask. Your whereabouts at about six o'clock Thursday evening?"

Chrissom looked insulted, but he let a breath out his nose and thought about it. "Yes, I suppose you would have to ask. I was having supper at home with my wife."

"Can anyone else verify that?"

"It was just me and my wife. But if you like I can call her and she'll tell you I was there."

"That won't be necessary, thank you." Again, handshakes all around. Don took a last look around the office, and then looked Chrissom straight in the eye. "If there's anything, anything that you think we should know, you have my card."

Chrissom broke the stare first. "Yes, of course."

Later, as they drove back towards the FBI building, Don tapped his hand with nervous energy on the steering wheel. "There was something he wasn't telling us. I'm sure of it. He was holding back."

"I agree. Those pictures frightened him, I think."



When Don arrived at the Eppes house that evening, he found his brother in the living room, ensconced on the floor by the coffee table, his legs folded beneath him and his dark curls swinging gently back and forth as he turned his head to compare the information on various pieces of paper laid out in front of him. His laptop was open in front of him. Alan was nowhere to be seen.

Charlie loked up as his brother entered and smiled a distracted greeting. "Hey, Don."

"Hey, Charlie. Dad home?"


"Really?" Don dropped his briefcase on a chair and pulled off his suit jacket.

"Yep. He seems to have taken to it." Charlie was searching through his pages and finally came up with a piece of printed sheet music. "I'm glad you're here. Want to do me a favour and try playing this? I need to be sure it's accurate."

Don took the sheet and glanced it over. "What's this?" His case, and the day's interviews, were still very much on his mind, and he had entirely forgotten about the music box.

"It's a fugue I composed for Dad's birthday," Charlie said with friendly sarcasm, and laughed at Don's raised eyebrows. "No! It's the song from that music box of yours."

"Oh," Don said. "Why don't you play it?" Charlie knew the basics of the piano, but had never learned to play well; he never had the patience for the practice it required.

"Two reasons. One, you're the pianist in the family, not me. Two, I've been listening to that song backwards and forwards for three days running and I couldn't be sure that I was playing what was on the page, and not what was in my head."

"Oh." Don laid his jacket ofver the back of the sofa and moved over to the piano. "You realize it's been years since I played,' he warned as he sat down and gently raised the lid. Automatically, his right hand sought out middle C.

"It's like riding a bike. You never forget."

"Yeah, says the man with the eidetic memory," Don returned, and Charlie just grinned and shrugged.

Gently, Don started tapping a beat on his knee with his left hand, mentally counting. Slowly, carefully he picked out the little melody, only tripping up once or twice, then played it though a second time with more confidence as his kinetic memory began to return to him.

"Okay, thanks Don, that's good," Charlie called, and Don set the sheet music aside, but didn't get up. He brushed his fingers gently over the keys, feeling the familiar smoothness of the faux ivory. The piano was still relatively in tune, and its sound brought him back to when his mother had sent his father out for a walk with the three-year-old Charlie and sat her ten-year-old firstborn beside her on the piano bench and began teaching him how to play.

As the boys grew, and Charlie's special needs began to take more and more of his parents' attention, their mother always made it a point to spend time with Don at the piano. When he outgrew her lessons and went on to other teachers, she still stayed near as he practiced, singing along or lending helpful, annoying advice - he could hear her now, calling from the kitchen where she was drying dishes: "Watch your F sharp, Donny!"

"Play something, Don," Charlie said softly.

Don reached into the piano bench, and pulled out the first thing his hand encountered - a bok of intermediate-level piano solos, well worn from many trips in his knapsack. It fell open as he put it up on the piano to Beethoven's "Moonlight Sonata", and softly, gently, he began to play, his mind filling with memories even as the tension began to bleed out of his shoulders and neck. His fingers, once again confident, faltered only rarely. He was only barely conscious of reading the notes - it was as though the notes on the page went straight from his eyes to his fingers without bothering to go through his conscious mind.

When he finished and turned around, he found Alan standing there in the open doorway, unwilling to close the door lest he interrupt the music. His eyes were glistening as he stared at his son.

"Thanks, Don," Charlie said, after a moment's pause, breaking the spell. Alan came the rest of the way in, and Don closed the piano.

"That was beautiful, Donny," Alan said. "You should - " he cleared his throat. "You should play more often."

"Yeah, maybe," Don replied softly, then shook himself and turned back to his brother. "So, what have you found with the music box?"

Charlie shook his head and shifted his legs under the coffee table. "Not much. I've learned that the song has been deliberately modified from the original, and the notes aren't completely patternless. Not many companies custom-build music box movements, and this is apparently very nice work. I have a list of possible companies, but I haven't started calling them yet. I wanted to get started on pattern analysis of the song itself."

"Any leads on what the message might be yet?"

Charlie stared at him, his eyes wide and incredulous. "Don, do you have any idea how difficult a ciphertext-only attack is? And I don't even know for sure that I have the intended ciphertext. Aside from a gut feeling that these notes are not random, and some mathematical tools, I have nothing to go on. I have, what, five or six lines of music - that's a very small sample to build an attack from. If I had some cribs to try, maybe that might help, but without them, well, it could be weeks if I'm lucky, maybe months, maybe never."

"But Charlie, you're great at finding patterns."

"Well, though I appreciate your confidence in me, it's not that simple. It's not just a matter of finding the pattern. Rather, what does the pattern signify? Music by its very nature follows distinct patterns - just think of the Sonata you just played - and any pattern I find in this could conceivably be merely residue of the original song. Or, it could be meaningful, but I'd stll need to find the equations governing it. You can't just pull this stuff out of the air, Don."

Don nodded apologetically. "Sorry. I guess I kind of take it for granted that, given a chalkboard and a piece of chalk, you can do pretty much anything once you get started."

Charlie grinned tiredly. "Thanks, but I wish. So how's your case coming?"

Don stood up, stretched, and fell into an armchair. "Slowly. I feel like I'm beating my head against a wall. I know these guys are dirty. I know they are. But the evidence is just not coming."

"Would some iced tea help?" Charlie levered himself up from the coffee table, and winced as his foot began to throb with pins and needles.

"That would be heaven."

Alan turned on the TV and sat back, letting music boxes and fraud cases flow past him. His family, all four of them, was together there, and he was content.

End Chapter 5

Learn about ciphertext-only attacks at the Wikipedia (link in my author profile).

Special thanks to kippling croft, Stephanie519/SD, Crystal Mak, Alamo Girl, Whyte Star, LotRseer3350, and umino-gaara for taking the time to review, as well as to those of you who chose to email me personally. I really appreciate all your comments, especially when I'm lacking in energy - your comments give me the kick in the pants I need to get writing again. I send virtual flowers to all of you. :)