"Won't help, Don. Sorry." Megan handed back the sheet of paper.

If anything, Don thought, Megan looked worse. It was always that way, when the bruises started to turn all colors of the rainbow and then some. Her black eye had turned purple, but now seemed like it was letting a slender sliver of light through to the eyeball underneath. She lay against the plastic pillow of the hospital bed, the white linens making her seem tiny and frail. The sling didn't help, binding one arm against the rest of her body.

"Because…?" Don let the question trail off.

Megan sighed. "Because they got a child to write it for them. Even writing with the opposite hand wouldn't produce this sort of handwriting. They were careful, Don. I'm sorry. It won't help."

"The kid?" Don looked back at David.

David looked blank. "Not that I know of. He didn't mention that they told him to write the letters. But we didn't ask him, either." Half a smile twisted his face. "And he got ten bucks from us, not just five. And ice cream."

"Sucker. Get somebody to go ask him. Maybe we'll get lucky." Don turned back to Megan. "Anything you can think of? Any leads to follow up?"

"I'm on drugs," Megan informed him. "I'm barely able to put two thoughts together, let alone think."

Don frowned; she was right. But there had to be some reason that they had targeted Megan, and the thought that she was the profiler didn't seem to ring true. "Get some rest," he finally said. "I'm keeping the security on you until we have them in custody."

"Don, I—"

"Not up for discussion," he told her. "You got everything you need? Want me to arrange for someone to help at home? Move in with my dad for a couple of days until you feel better? You know he likes you."

"Your dad likes everyone," Megan agreed. "He's one of the sweetest guys I've met. I can see how you and Charlie turned out the way you did. Thanks, but I'd rather just go home and sleep in my own soft bed where alarms aren't ringing half the night. You don't really need to have anyone stand watch—"

"Like I said, not up for discussion," Don interrupted.

Megan smiled wanly, giving in. "You'll keep me posted on the progress?"

"You got it."

Don slid into his seat at the chair, handing out copies of the paper with Megan's photo on it to the surviving members of his team seated around the table. He'd shuddered over the first one, but was finally getting inured to the sight of her lying crumpled on the concrete. It still made him angry, and he resolved for yet the hundredth time to get the bunch that had done this.

"I just heard from Tech," he announced. "They found the tracer that we put into the suitcase. Our perpetrators flushed it down a toilet somewhere east of the sewers. It didn't take the suspects long to detect it."

"They were looking for it," was David's opinion. "They probably expected us to try something. Anything on the bomb itself?"

Don shook his head, ignoring the residual head ache from yesterday. A good night's sleep had done wonders and carefully not having dinner with Charlie and his dad had prevented the pair from fussing over him. "There are a few leads to run down on some of the materials used in the bomb, and the Bomb Squad is running them. They'll report back to me when they have anything solid. Captain Winters said that he doesn't think they'll get much. Whoever put the bomb together knew what they were doing, made most of it out of common household items. Said that takes some real good knowledge of how to make things go boom."

"But surely that narrows down the search parameters," Charlie put in, looking up from his note-jotting. "How many people know how to build a bomb from scratch? And have access to the right materials?"

"That's just it, Charlie," David said, "there are a lot of them out there. Most are perfectly legitimate. They learned in college chemistry, need the information for other things. I'll bet that some of your students could do it right now. That doesn't make them suspects."

Charlie had to agree. "Probably Larry Fleinhardt knows as well. I could almost certainly research it pretty easily."

"See?" Don said. "But neither you nor Larry are a suspect."

"Larry likes Megan. He wouldn't try to hurt her."

"Good reason right there," Don agreed.

"But you're getting closer."

"We're getting closer," Don acknowledged with a certain satisfaction. "This whole bomb affair was a mistake on their part. We now know that someone on their side has to have some extensive knowledge of explosives. Despite my disparaging comments, that does narrow down the playing field. Hopefully, today's phone call will narrow it down some more. We didn't play by the rules this last time. We found the bomb before they expected us to. They're not making us look so foolish, and they won't like that. They'll be out to make us seem utterly ridiculous on this next caper, and they'll be working hard to do it. They'll make mistakes. They'll give us the opportunity to take them down."

"Right." Charlie stared at the phone, expecting it to ring. It had for the last several Mondays, Wednesdays, and Fridays.

David fiddled with the tracking equipment.

Don stared at the white paper, seeing Megan fly through the air, over and over. Saw her smack up against the aquarium brick wall. Saw her fall.

Charlie watched the phone, waiting.

David waited.

Don waited.

They waited.

"What if it doesn't ring?" Charlie asked.

"It's going to ring. It always has."

"They need to make us look bad," Don agreed.

He waited.

David waited.

Charlie waited. Charlie looked around; he'd finished his notes for tomorrow's lecture, and hadn't brought anything else to pass the time. He looked around some more. "How's your head, Don?"

"Fine. How'd you know about that? You tell him, David?"

"Not me, Don."

"What, I can't be observant?"

"Charlie, you're as observant as…as…" Don cast around, trying and failing to think of a reasonable simile. "Charlie, you're oblivious to the world."

"Not all the time."

"Most of it."

"Only when I'm working on a problem."

"Which is most of the time. A bomb could go off in the room next to you, and you'd go on solving whatever." The moment he said it, Don winced. That comparison hit a little too close to home. There was a bus on the road with passengers who were safe because Don and his team has successfully defused a bomb. And if one or more of the criminals were experts in demolitions, more bombs could be expected. Don didn't want more bombs. He wanted to catch these sleaze balls and put them where they couldn't make any more bombs.

He waited.

David waited.

Charlie waited.

"How's Megan?"

"She's home."

"Oh."

Don waited.

David waited.

Charlie waited.

"Dad get off on his trip okay?"

"Yeah. He drove out this morning to the airport. Should be landing in Vegas," Charlie consulted his watch, "should have landed half an hour ago."

"Staying with that friend of his?"

"Rudy Gallagher. Yeah, I've got the phone number at home in case anything comes up."

Don waited.

David waited.

Charlie waited.

"Maybe this time they won't call," David suggested.

"Bite your tongue. I can just see explaining to the deputy director why you and I and a highly paid consultant who happens to be my brother spent the afternoon doing nothing. Can you say 'very expensive nepotism'? They're just making us wait. Making us nervous."

"It's working," Charlie said. A pencil snapped in his fingers, and he started. He sheepishly put the pencil pieces down, then picked the two halves up and tossed them into the trash can with a embarrassed look.

"Colby getting anywhere with his security tapes of cell phone users?" David asked.

Don shook his head. "Not yet. He's already canvassed over thirty people, all of whom have cheerfully given him permission to research their calls for the last month or more." He sighed. "You'd think that at least one of them would have something to hide. A mistress, a gambling debt, even a surprise party for the neighbor's dog."

"They're walking near an FBI building," Charlie pointed out. "People with something to hide tend not to do that. At least, not by choice."

"Which is why we're not getting anywhere with that lead," Don sighed. "I don't know about you, but I'm getting damned tired of being jerked around like—"

Ring

The dance had begun. Don once again went to pick up the handset, pausing only for David to start his own equipment. His pulse began to race. This was it. "Eppes."

"Are you the Eppes who solves my riddles?" Still sounding like Stephen Hawking on a bad day.

Don caught Charlie's eye. "Yes." And, "I solved your last one. Didn't work out so well, did it? Not quite ready to retire yet on your earnings from the last job?" Don leaned forward, knowing that the attitude would get into his voice. "I've got a great retirement plan for you: three hots and a cot. Great security. Even has solitary confinement when you need some time to yourself, a little getaway when the rest of the lads get a little too friendly. Of course, you don't get any choice over roommates, but we can't have everything, can we?"

The computer voice digested that. Then: "I don't like you."

"Isn't that too bad?" Don sneered. FBI Advanced Negotiating Tactics: push the suspects into mistakes born of anger. "It's really tough when you're not good enough. Those little riddles of yours? Get a life. Anyone uses simple stuff like that, we laugh 'em out of the business." He hardened his voice, and exchanged a look with David. "Or they get shot." He glanced over at Charlie, wondering how his younger brother was taking it. Charlie's eyes were round, but he kept a clamp on his mouth, watching every move Don made.

"C'mon, c'mon," Don urged, keeping the smirk in his voice. "Got another one of those little messages for me? Almost caught you last time. Probably do it this time. Got a real nice judge lined up for the arraignment. Can you afford an attorney? Probably not. We'll be sure to scrape the bottom of the barrel for you."

"Now I know that I don't like you," the computer voice said. The person behind the voice seemed to gain inner strength from somewhere. "And I doubt that you have been solving the puzzles. Good bye." Click.

"Hey," Don objected, "what about the riddle?" But he was talking to dead air. "David?"

"North part of the city," the man reported, "but nothing more definite than that."

"It's a start," Don acknowledged. "You've ruled out three-quarters of the city. What's that? Half a million inhabitants?"

"The last census, using sampling techniques to account for the undocumented—"

"Figure of speech, buddy. David?"

"I'll get some of the guys in Tech to give me a hand," David said. "Maybe they can squeeze something out that I can't." By the tone of his voice, he didn't believe his own words.

Charlie watched the two FBI agents work, at a loss for himself. With no riddle, no code to solve, there was nothing for him to do, no problem to work on. "Don?"

Don recognized the signs immediately. "Sorry, Charlie. Looks like we're not going to be able to use you this go around."

Charlie disagreed. "There's a pattern here, Don. I can almost see it. I need a little time, time to work out the equation that will show the pattern—"

"You think you can figure out where these clowns will hit next? Even without their stupid little codes?"

"The codes aren't really part of it. I can run it through some multi-variate analysis, see if I can come up with a solution with p equal to point zero five or better—"

"Do that," Don ordered, hoping his eyes weren't glazing over. They tended to do that when Charlie started babbling.

"Uh, I need to get back to my office." Charlie looked hopeful. "I've already started it there, and I think with just a little more time, maybe an hour or two, I can come up with something pretty solid. I jotted down some of the things from the case files, some of the details…"

"Right." Don glanced around. "I'll take you back to your office, drop you off. You work on your equations, and call me when you have something. I'm counting on you, buddy," he added. I really have more faith in squeezing my sources at this point, but I'll take anything I can get. "There's not much here. You sure you can find a pattern?"

"It's human nature, Don," Charlie told him. "We all fit into patterns. We can't help it."

"Isn't that profiling?" David muttered under his breath, watching the brothers exit.

"Just drop me off at the main entrance, Don," Charlie directed. "Parking lot's full."

"I'll find a spot." Don concentrated. There one was, a slender box of tarmac about as far from the Math Building as it could be and still be considered part of the parking lot. Don had been unusually quiet during the drive over, thinking. And the thoughts that had been running through his mind hadn't been to his liking. "I'm coming in."

"Why? You hate coming in to my office."

Don pursed his lips. "Let's just say I've got a funny feeling."

"And that means—?"

Don stared ahead, looking at nothing. "Oh, all right. Charlie, I'm getting a hinky feeling about this whole case. Remember how that voice wanted to talk to the 'guy who solved the riddles'?"

"Right. That was you. That's what you told him. He bought it."

Don looked away. "Charlie, he was talking about you. You were the one who deciphered all the codes."

"Don, anyone could have done that. Those were not difficult codes. Your people—"

"But not as fast as you, Charlie. He wanted to talk to you. He thought it was you, when you gave me the cube root thing. And after what happened to Megan…" He allowed his voice to trail away. He summoned his courage. "Charlie, he said he didn't want to talk to Megan any more, and then he took her out with a well-planned execution. We're all really lucky that she's walking out of the hospital alive. Buddy, I don't want that to happen to you."

"But he doesn't even know who I am," Charlie protested. "He doesn't know I exist, let alone helping you with this case."

"Beg to differ, buddy. He asked for Eppes."

"But that was you. Unless you've changed your name recently and neglected to let Dad know."

Don took the keys out of the ignition. "I'm not taking any chances."

"You're walking me to the front door of the Math Building? It's broad daylight! I'm a grown man, Don. I don't need a babysitter!"

"You're not getting one—yet. If I find anything I don't like, then you will."

"And just what is it that you won't like?"

"I won't know that until I search your office."

"My office? Don—!"

"The house is probably not a good place," Don continued as if Charlie hadn't said anything. "They know that Dad lives there, too, and it would be harder to plant a bomb undetected. Although they may be aware that he's out of town. I'm going to have the Bomb Squad do a run through."

"They never use the same M.O. twice! They won't use a bomb again! Statistically—"

"So that leaves your office as the primary target area," Don interrupted. "I will search the place for anything suspicious, then I will leave you to your numbers." He grinned encouragingly at his younger brother. "Remember, buddy, I hate being in there. It's messy, and you probably grow cockroaches somewhere in a drawer. I won't stay any longer than I have to."

"Probably afraid that you'll learn something if you stay," Charlie muttered under his breath.

"What was that, Charlie?"

"Nothing, Don. Coffee?" Charlie grabbed at a couple of Styrofoam mugs on the way through the main reception area. "Don't smudge any of the white boards when we get to my office. Those are your equations on them."

Don made Charlie wait outside the office while he examined the interior. He hadn't been joking when he'd said that Charlie kept the place in a state that even chaos wouldn't admit to. Mountains of papers overflowed their bins, cascading onto the surface of the desk so that there was no longer any room to work. Even the computer keyboard was hidden by sheets of white with multi-colored scribblings in a multitude of different hands. It would be a handwriting analyst's field day in here, should a crime ever be committed in this office, Don reflected. Come to think of it, the criminal mastermind had better plant a bomb, contrary to Charlie's predictions. Blow up the place, get rid of the mess, and start over. Clean the place out. It was probably the only thing that ever would. A simple sniping through the window would only add to the mess. Don cringed; he glanced out through the window, automatically cataloging the best angle for a shot from the building across the courtyard. Should he check that building out, too? Not a bad idea. He pulled the shades closed, intending to keep them that way until he could make that inspection happen.

He saw Charlie's equations hand-written on the white board. His younger brother had used three different colors but without help Don wouldn't be able to tell whether it was deliberate or whether Charlie had simply run out of ink. According to Charlie those were the beginnings of the solution to this case, a way to predict where the 'mastermind' would strike next. It seemed incredible, it didn't seem possible, but Charlie had made similar predictions for other cases that had turned out to be astoundingly accurate. Charlie had made a believer out of his older brother. Not that Don would admit to it in front of Charlie. Gotta keep a little of the sibling rivalry going. But on a case?

He stirred around through all the papers, anywhere that a bomb might be able to be placed: corners, drawers overflowing with odds and ends. He opened a small closet and actually found a broom with tattered straw for a working edge. "And here I keep hearing how he works in a broom closet," he muttered to himself, well aware of Charlie waiting impatiently outside for the all clear.

"You find anything?"

"Not yet. Keep back."

"You're not going to find anything in there."

"Neither can you. This place is a pig sty! How can you do any work in here?" No, that bag contained an old left-over PB&J, along with a healthy helping of mold. That could be discarded. Don gingerly dropped it into the trash can, trying to remember if there was a men's room with running water and soap at the end of the hall. Next stop: sanitation. "The office is clean. And I use the term to mean free of explosives, only."

"Thanks. I've got office hours in another hour." Charlie repossessed his office. He glared. "You moved stuff. I had it organized."

"So sue me. This my equation?"

"Yeah. But I gotta grade some papers first. The class is expecting them back tomorrow morning, needs them to study for next week's mid-terms. I'll work on your equation during office hours."

"Don't you see students during office hours?"

"Nobody scheduled. Someone might drop in, but that's a sixty-four/thirty-six proposition."

Don groaned. "You've calculated the probability of a student coming to see you unannounced?"

"No. Made those numbers up. Just wanted to hear what you'd say." Charlie grinned, pleased to have put one over on his brother.

Don shook his head. "I'm out of here. Keep the shades down, and wait for me to come get you tonight. I'm dropping by Megan's. I want to get her take on the last conversation we had with our criminal mastermind. I pushed him pretty hard, and I'm not certain how he reacted."

"We didn't get the clue that he usually sends."

"No, and that's worrying me. This type of guy, he wants to prove that he's better than we are. He should keep making the clues harder and harder to solve. This guy just threw a hissy fit and hung up. He was miffed."

"It's not in character."

"That's just it; it's not in our character. But it is in his. 'Cause he did it." Don jerked his thumb at Charlie's equations. "Think you can factor that in?"

The glazed look was already stealing into his younger brother's eyes. "Yeah. All I have to do is figure out how to apply Raymond's Potential without negating the effects of the Personality Dimension Analysis, and…"

Don let himself out quietly.

Wonderful invention, cell phones. Don couldn't imagine conducting his job any other way, couldn't even remember a time before that. Looking for phone booths all the time, making sure to have change to activate the damn things? Not a chance. Made a great story for the old-timers to share. To hear them tell it, entire cases hung on the chance that the corner pay phone would be working or not. Don used his cell to call Megan at her home.

"Megan? How are you feeling?"

"A lot better, thanks. What's up?"

"Better? Really?"

"No, not really, Don, but my mother brought me up to be polite on the phone. I can't tell you how I actually feel without making her ears burn several hundred miles away. How's the case going? You promised to keep me updated. I have a personal interest in this one, you know."

"Yeah, I kind of figured that." A lot more coherent was Megan, especially when compared to yesterday in the hospital. Don grinned. That was good. He needed her skills, needed her as someone to bounce ideas off of. Both David and Colby were good at their jobs, but Megan came with an entirely different perspective. And, dammit, he was getting tired of chasing this dude! "Listen, you up for some company?"

"I'm not about to get all dolled up, but if you can stand seeing me in sweats and bruises, you're on." Don could hear the grin in her voice. "Besides, you gave me a chaperone. Sherry is here."

"Sherry from Enforcement?"

"Yup. She wanted the overtime. All I had to do was show her where the stash of caffeine was, and she let me sleep."

The smile froze on Don's face, even though Megan couldn't see it. Sherry from Enforcement wasn't a standing joke because no one dared joke about the woman. At six foot one with one hundred sixty three pounds of shapely muscle, Don was certain that the woman could bench press more than he could, and Don was not out of shape. This FBI office had needed a woman who could handle any female suspects, and Sherry more than fit the bill. Megan kept insisting that Sherry had a great sense of humor but so far, Don hadn't seen it. You would if you were a woman, Megan told him.

Thanks, but I'll pass.

"I'll be there in a few," he told her. "Listen, I'll see you. There's another call coming in."

"I'll expect you."

Don clicked the call off and caught the second before voicemail could grab it. "Eppes."

"Don?"

"David? What's up?"

"Don, another fax came through. Our mastermind sent the next clue."

"Finally. Coded?"

"Yeah, but—"

"Fax it over to Charlie's office. I'm over here right now. I'll get him a copy and work it right here. You got the number? It's in my desk, right hand drawer, top."

"Don, wait a minute. Listen to me! That's not all that's on this fax."

Don felt ice settle somewhere deep inside. "What else?"

"It's a picture of Charlie, Don. It's a picture of him coming out of headquarters with you. And, Don, there's a sniper's target superimposed on his face."

The ice turned into a massive glacier. Dammit, he'd known something was hinky! He'd done right to insist on searching Charlie's office before letting his brother in, and now was very glad that he had. His brother kept his office open and unlocked all the time. It would have been child's play for someone to plant a bomb there. He glanced up toward where he knew Charlie's office was, third floor toward the end; the window shades were still drawn. Good; he wouldn't have put it past his brother to absent-mindedly roll them up because he needed more light. It would be all too easy for a sniper to take up a position with a line of sight at Charlie.

"I'm outside his building now. Get a bodyguard team down here ASAP; I'll stay with him until they get here. Have the Bomb Squad do a search on his house; they can get the keys from me, but I'm betting that this kook is going to try an assassination attempt. That's what that sniper's target symbol must mean and there are plenty of excellent sites for a sniper right across the quadrangle from Charlie's office. Fax the sheet over, and I'll have Charlie take a look at the code—"

Having lived in L.A. for most of his life, Don was familiar with earthquakes. He'd lived through quite a few. What occurred next bore a significant resemblance to an earthquake in that the earth rumbled under his feet. What was different was the noise: it blasted his eardrums louder than any rock concert and certainly not like any earthquake he'd survived. What was also different was that the blast took out several windows on the third floor of the Math Building. Papers careened out through the broken panes, floating down as gently as feathers.

Charlie's office was on the third floor.