The doorman wasn't much to look at, and was even less of a pleasant sight after sitting alone in Interrogation Room One for almost an hour. The wait was getting to him, that Gibbs could easily tell. The hair had gone lanky with sweat, and the collar had been pulled open by nervous fingers, allowing a few scant and dark chest curls to seep up over the top button. The man's eyes darted continually around the bare room, trying to find answers written on the empty walls. It wasn't working.

Gibbs chose his moment to enter. Timing was everything; the decision of a suspect to spill his guts would be made in a split second and that second couldn't be rushed nor delayed. Gibbs sauntered in, hiding his own level of anxiety, noting that the suspect failed to regard his captor with a faint air of supercilious superiority that seemed to mark the really difficult culprits. Good; that meant that this one would crack fairly easily. The bad part was that anyone who cracked easily usually didn't have much to offer in the way of evidence or clues. Gibbs would rather have had a more difficult time.

Still, this would be a performance. One of the FBI people, the one named Sinclair, was outside of the room, watching him work. Gibbs didn't particularly like it but didn't have much of a choice, not if he wanted Fornell to play ball. Fornell was FBI, and had drafted the out of town talent. To be honest, they had as much at stake as Gibbs, since the consultant guy was the brother of the lead L.A. guy, but at the moment that wasn't helping Gibbs's mood. Gibbs was damn good, but that guy outside Interrogation Room One would be judging his every move and Gibbs wasn't in the mood for a critique.

"Don't bother getting up," he told the doorman, ignoring the fact that the man hadn't tried. Not the point; Gibbs simply wanted the man off guard, wondering what a guilty person was supposed to do at a time like this. Gibbs perused the information in a manila file that Ziva had just pulled off the computer for him. "Jackson Darby, of 1015 Wilding Way. Well, Jackson Darby of 1015 Wilding Way, you are in a hell of a lot of trouble." He deliberately kept his tone mild, knowing that it would cut far deeper than any angry shouting.

"I—I don't know what you're talking about," Darby stammered. More sweat popped out to join the first droplets. "I didn't do anything!" The last line was almost a wail.

"No?" Gibbs pretended to read from the file. "How does 'treason' sound?" He leaned in from behind to whisper in the man's ear, "they execute people who threaten national security."

Which was stretching the truth, since Gibbs wasn't even certain that he could charge this man with anything much besides idiocy, but that wasn't the point. He wanted visions of getting strapped down to a gurney with a syringe being inserted into a vein to float through this man's head.

The doorman tried to summon a spine. "I want a lawyer," he squeaked, the effect he was going for ruined by his vocal cords' lack of cooperation. The basso emerged as a cracking falsetto. He cleared his throat, and tried again. "A lawyer. I'm entitled."

"Suit yourself," Gibbs shrugged. "Of course, any offer I have goes away once your mouthpiece hits the door." Let's impress the poor slob with language straight from The Sopranos. Any real crook would be laughing hysterically by now.

Darby gulped.

"Besides, I haven't yet charged you with anything. Only guilty people start screaming for a lawyer." Gibbs continued to 'study' the file. "Of course, there's always the possibility that the only thing you're guilty of is stupidity." He let the words hang there in the breeze, dangling and waiting.

Another hard swallow. "What offer?"

Gibbs forced himself to remain calm. "The one where you tell me what I want to know, and you go home to sleep in your own bed tonight." He shrugged once more, and pretended to consider the prospect. "That's assuming that an enemy sniper doesn't plug you as you walk out through the front door of this building." Like that would happen.

"Sniper?" Working on high C. "I—I didn't…You can protect me?"

"Your best protection is to tell me everything you know," Gibbs assured him. "They won't touch you after that; there would be no point. That would only get them into more trouble. Nobody is stupid enough to risk a murder conviction without a really good reason, which you get rid of by telling me everything." Of course, Gibbs and the others didn't know who 'they' were, but bringing up the concept of a revenge killing that wasn't about to happen wouldn't hurt the 'crack the suspect' scenario going on.

"Murder." The doorman's hands were trembling. Not the proper word, Gibbs decided cynically. Not trembling; shaking. Not even salt shaker type shaking, but earthquake cracking wide open to rival the Grand Canyon.

Good.

"I only saw one of them," the doorman whimpered. "He gave me a thousand bucks to tell him when two certain guys had gone into the room, and then to stand there and not let anyone else in. Please, mister, I was desperate! I've been out of work for three months! I needed the money, and they just told me to do what my boss told me to do anyway. Nobody was supposed to get hurt!"

"Really?" Gibbs finally seated himself across the table from Darby. "Two prominent scholars were kidnapped, two men who work at some of the highest levels in government." It sounded good. "Take it from the top. Who approached you?"

There wasn't much the Darby could tell him. Someone had called him on his cell phone, promised to give him money to make a call when Professors Eppes and Penfield entered the salon that Darby had been assigned to monitor. Gibbs passed out the information immediately, knowing that the phone that had called Darby would turn out to be a burn phone, a dead end. Darby himself had thought the whole thing to be a prank—until he found five hundred dollars in an unmarked white envelope in his locker. It was the half up front that he'd been promised.

That made it a hell of lot more real. The task wasn't hard; people had identified themselves according to a list that the manager had given him. Dr. Eppes was on that list, and so was Dr. Penfield. McGee was not; not that Gibbs had expected him to get in. McGee was certainly good at his job, but joining into a private soiree for math geniuses was above his pay grade. What was the answer there?

Whatever it was, was not immediately forthcoming. Four more men had approached as a group, and had handed Darby another envelope. Gibbs had already confiscated it and handed it over to Abby for prints. Not that he expected there to be any, but it was standard procedure and people sometimes got careless. Gibbs wasn't about to turn down any offered lucky breaks.

Darby had recognized the type of envelope, and accepted it. The four men hadn't said anything, had just entered the room and shut the door behind them. That was that; nothing more. There were no sounds, nothing to indicate that anything was out of the ordinary. The only thing that Darby could actually say was that he let in four men in business suits but without conference ID cards that allowed them legitimate access. Not such a big crime, and the pay had been good.

Not good enough. Gibbs tossed a picture of Dr. Charles Eppes onto the table in front of the doorman. "Recognize him?"

"Uh…he's one of the people that I was supposed to watch for? Penfield? Eppes?" Darby was clearly rattled.

"Professor Charles Eppes," Gibbs told him sternly. "Probably gonna get a Nobel Prize before he's through with his career. That's assuming that your actions haven't gotten him killed. How about this one?" He slid a picture of McGee across the table.

"That's the other one," Darby said immediately. "If the first guy is that Eppes, then this one was Penfield. I saw him come in, then I closed the door."

"How did you know that he was Dr. Penfield?" This might be part of the answer. Gibbs held his breath.

Darby frowned. "He had an ID card on him. I passed him through, like they told me. Check the ID against the list, and let 'em in. Mister, I just wanted this thing to be over with! I was scared, 'cause it was getting real!" Darby turned panic-stricken eyes upon Gibbs. "They're gonna kill me?"

"Not if I have anything to do with it," Gibbs reassured him, knowing that it was only the truth. Chances of anyone going after this poor dupe ranged between 'slim' and 'none'. He pulled one more photo out of the manila folder. "And this man?"

Darby recognized the face immediately. "This is the guy who was hassling me about going into the salon. He didn't have no ID, so I wouldn't let him go inside. He got mad, and went off to talk to the concierge. Then you guys showed up, and it hit the fan."

There wasn't much more to get from this guy. Gibbs knew it, and the FBI agent outside the one-way glass knew it. Gibbs pulled the photos back and slid them into the manila folder, McGee's face staring up at him. Gibbs resolutely closed the manila cover over it, shoving emotions and fear down to where it wouldn't interfere. "You're going to meet with a sketch artist, see if you can give us some clues about these men that you worked with."

"You're…you're not gonna lock me up?"

"Do I need to?" Gibbs made his voice deep and foreboding with only a minimum of effort. "You planning on leaving town?"

Darby gulped. That had been exactly what he had been planning to do: take the money and find a hole to crawl into until everyone had forgotten that he existed.

Gibbs read his mind. "Wait here," he told the doorman. "Somebody will come get you."

Gibbs walked out through the door, pausing to pick up the FBI guy—Sinclair, was his name—and headed off toward the bullpen. "Not much this guy can tell us. Anything to add? Anything you picked up from the interrogation?"

"Just one thing." Sinclair kept walking.

Gibbs halted on a dime. "What?" What did this FBI guy think that he'd picked up and Gibbs hadn't?

Not even a ghost of a smile. "There is no Nobel Prize for math."

"Asynchronous, without a doubt," Professor Eppes said, scratching on a pad of paper, his pencil worn down to a nubbin.

"Asynchronous," Penfield-McGee agreed.

"Try the Ben-Azariah pretension. Let's see if we can get it to open up."

"Already?" the fake Penfield asked. "Shouldn't we try the Glovcheskian approach first?"

Professor Eppes halted, and stared at McGee. "You're right. Glovcheski, it is."

McGee took a deep breath. Message received. Professor Eppes, it was clear, would dive headlong into any puzzle no matter what the circumstances. Working at anything less than warp ten was categorically impossible for the man, as was paying attention to extraneous details such as working for an organization that had just kidnapped them.

Another one of those details, McGee was almost certain, was that they were being watched or at least listened to, although not all the time. If that had been the case, then McGee would already be dead after the discussion that he and Dr. Eppes had had as to McGee's real identity and how he came to take Dr. Penfield's place. According to Dr. Eppes, that was fortunate for both Eppes and Penfield; Dr. Eppes seemed to think that Dr. Penfield would have reacted in such a way that he'd get a great deal more damaged than Special Agent McGee already had. Dr. Eppes, though, believed that he himself would have behaved far more circumspectly since he had had the advantage of exposure to FBI methods through both his work and his brother. Dr. Eppes also had had several years of working with such agencies as the NSA, among others, which surely gave him a superior comprehension of the workings of the intelligence community.

McGee, remembering the previous events a bit differently, declined to argue.

All of which led to the current discussion: whenever Eppes seemed to be too prepared to rush forth with an answer to the code for their captors, 'Glovcheski' was the term that they had prepared between them to reel the professor back into reality.

It was a delicate balancing act: Special Agent McGee really wanted to know the contents of the coded message that they were working on. Any code for which people went to these lengths to get deciphered had to be something that would cause world leaders to tremble, which meant that McGee wanted to know what it was so that he could do something constructive with it. That was also the problem: 'constructive' didn't include letting their captors know the message, and that was going to be somewhat problematic. McGee snorted; let their captors get one whiff that the code had been cracked, and McGee and Eppes would be lucky not to be cracked themselves. No, the best way to handle this was to proceed as slowly with the deciphering process as possible. If they didn't know what the message said, their captors couldn't get it out of them.

Not too slowly, though; if 'Ms. Marple' thought that her new employees were dawdling, McGee was certain that neither one would like the consequences. His ribs ached irritably, reminding him that he had already had a taste of her displeasure and that he really shouldn't request a second helping if at all possible.

All of which meant that the procedure for the two captives was to dawdle at the code-breaking while searching for a way to escape. McGee automatically glanced around; if it came down to it, he'd settle for getting only Professor Eppes out of here. McGee had no desire for a premature death, but he had to face reality: Eppes was the one who could decipher the code and McGee could not. Eppes had been very complimentary over McGee's computer skills but that wasn't going to solve the puzzle. McGee knew his limitations, just as he knew that Professor Eppes's limitations included an inability to devise an escape route from this well-appointed jail cell.

McGee scanned the workroom once again, still hoping to figure out how to get one or both out of this mess. This particular room was subterranean, perhaps the finished basement of an old mansion. The ceiling was tall—McGee estimated that it was at least ten feet—with track lighting that illuminated every nook and cranny of the room. Whoever had furnished the place seemed to think that the inhabitants would spend the majority of their working hours there: a sitting area with two sofas to provide a 'conversation nook' and a small kitchenette beyond stocked with a selection of bottled water and healthy snacks. Eppes had taken one look and made a face; their captors, it was clear, had researched the habits of their new employees and were expecting to maintain them in this place for the foreseeable future. This was not a one-shot deal.

McGee was both heartened and dismayed by the prospect. It diminished the possibility that Ms. Marple considered them as disposable once this code was broken, but it also suggested that she had invested a great deal of research as to how to offer Eppes and Penfield a 'deal that they couldn't refuse'. Wait—obviously not enough research, or she would have recognized immediately that McGee wasn't Penfield, and that would have been fatal for one NCIS Special Agent Timothy McGee.

Opposite the 'living room' was a large pad of paper on an easel that Eppes had covered with numbers and letters, not all of which were in English. This was the work area, outfitted with two high end computers. McGee's mouth had drooled as soon as the main display had come on: this was almost as good as the set up that he'd assembled in his own home, piece by piece, tweaking the system until—he lied to himself—that the next upgrade would need to involve something with the logo 'Cray'.

Any hope of sending a message through the internet had been dashed within seconds. Ms. Marple had obviously anticipated the possibility and had countered it by removing the hardware. At first McGee had hoped that she'd merely turned off the internal modem; no such luck. The woman realized the quality of genius that Eppes and Penfield possessed and took steps to prevent either from calling for help. McGee himself was good with making computers turn cartwheels but even he couldn't access the Internet without the proper equipment. He was stumped.

The windows? Best bet. There were two of them, spaced some ten feet apart and partly submerged by grass which had told McGee that they were located in the basement. Professor Eppes, with his smaller build, would be able to wriggle out but McGee would have a harder time of it. McGee found his gaze drawn back to the glass over and over again, eying the rims of the windows and mentally debating which one would be the easiest to get through—and how. Neither one was designed to open, which meant either smashing the glass—and McGee had already dismissed that as too noisy and too likely to draw their captors—or somehow removing the glass in a silent and covert fashion.

"Yo! Penfield! A little help here!"

"Oh. Right." McGee came back to reality, pulling his attention back from the window and onto what Dr. Eppes was indicating on the easel. He scowled at the equation, thinking that this was entirely too much like sitting in a classroom once again, waiting for the final exam to be handed out. "You added a sigma to the left side. Wait a minute; shouldn't that sigma be negative?"

"Nope. Double negative, Penfield," and Eppes emphasized the pseudo-name, "so the sigma ends up positive. And here, look at the alpha sub-one minus the alpha sub-two; it handles the negative over on the right, so we're equivalent."

"Right." This was why McGee had drifted to computers. Let the electrons handle remembering which was positive and which was negative. It was what they were good at. McGee just told the computer what equations to plug in.

Dr. Eppes apparently had a computer for a brain. The positive and negative equations simply flowed, as did the pieces of the answer.

It was flowing now; McGee already, in their short acquaintance, knew the signs. Eppes was staring at the paper on the easel, fingers twitching as though they held a marking pen, the glazed look spreading over his corneas indicating that comprehension was arriving.

It was replaced by fear, and McGee felt his own gut tighten. "Dr. Eppes?"

"It's there," Eppes whispered, his face ashen.

This was so not good. McGee had been counting on stalling for another day at least; another day for the authorities to try to track them down. Surely the FBI was on the trail; McGee couldn't count on his own fellow agents—Gibbs was good, but come on! It was Friday night, with a week end coming up, and the only reason that Gibbs would try to call McGee was to tell him that the espionage case was heating up. If that didn't happen, Gibbs wouldn't think about his junior team member until Monday morning—but Eppes was well respected and even more to the point, was expected to show up Saturday morning at the Pentagon to discuss something pertinent to national security.

Still… "What is it?" McGee asked, half-dreading the answer.

He was right; Eppes turned haunted eyes on him. He kept his voice down. "They're planning to bring in a shipment of a bio-weapon. These are instructions for where to pick it up."

Slivers of ice ran through McGee's veins. This was it. This was the big one, something that he and his fellow NCIS agents and every upstanding American had sworn to prevent: an attack on American soil by the enemy. It was something to rival the Twin Towers, and it was staring them in the face.

The question was: what could they do about it? McGee steeled himself and asked the question that he dreaded: "Where?"

Eppes looked away. "I'm not sure. Not yet. I can have it in…" he trailed off.

"It's going to take a while," Penfield-McGee insisted grimly. "There are a lot more possibilities to sift through before we can get pinpoint the exact location."

Eppes matched his unhappy expression. "A lot," he agreed.

"Got it, boss—er, Agent Eppes," DiNozzo stammered, turning the name around on its ear.

"Right here, Tony." Gibbs walked in on his man's sentence, neatly swiping the attention away from Don.

Don couldn't help but be impressed. His opposite number on the NCIS team effortlessly led his team; there was no doubt as to who was in charge in the bullpen. Gibbs took over the room merely by entering.

Not important; Don would let the Devil himself lead the team if it would get Charlie back to him in one piece.

Furthermore, Don could see DiNozzo relax as soon as Gibbs spoke. The implication was obvious: this was a team who had dealt with other agencies and did it by closing ranks against intruders from different branches of the same government. Don avoided clenching his lips, refusing to give anything away. This was not the time for a turf war. There were more important things at stake, and Don himself had had the misfortune to participate in his own share of turf wars.

That didn't mean that Special Agent Don Eppes was going to let anything slide by.

"I ran Schinoff's cell phone records, boss," DiNozzo announced, aware that the FBI team was listening closely. "He didn't make too many calls: three to his dry cleaner's, two to an overseas number in Greece, and one to a residence in Tyson's Corner."

"Run it down, DiNozzo. Who does the residence belong to?"

"Already got it, boss. Someone by the name of Jorge Santos, no known arrests or convictions, nothing but a clean driver's license."

"Any connections?" Colby couldn't sit still.

DiNozzo flicked the out of town guest an unreadable glance. "None that are popping up in our database. Not yet, anyway."

"We'll need to check him out," Gibbs decided. He scanned the group of three FBI agents, his own expression hooded, figuring out how to use the manpower without getting someone killed or fired. "We won't be able to do anything about the calls to Greece so this Santos guy is our best bet. Ziva, check out the calls to Greece anyway. Schinoff said something about Leonard Kwitarunge, so we'll assume that the Greek calls went to him—at least, for now. DiNozzo, take…" He cocked his head.

"David, go with him." Don made the decision for his team. "Colby, help Officer David track down the calls to Greece. Access our own databanks and see what pops up. Make sure that Kwitarunge is in Greece, at least."

"On it." Colby Granger, man of action, swallowed his disappointment.

More from Gibbs. "After that, make a visit to the dry cleaner, Ziva."

Puzzling. Don had expected to pair up with the NCIS team leader to explore that very lead. Why the hell would anyone call their dry cleaner three times? It sounded promising, and Don very much wanted to personally track down promising.

Gibbs had other ideas. "You're with me, Eppes," he instructed.

He'd play along—for now. Fellow FBI agent Fornell had vouched for the competence of these guys, although not without a malicious glint in his eye, so Don was willing to follow Gibbs's lead for the moment. Gibbs knew D.C., and Don did not. He followed Gibbs into the elevator, noting the height of the man, the straight spine, figuring that somewhere in this man's past the military figured prominently; Marines, probably, though another branch was always a possibility. If Don found himself in a dark alley with this NCIS man, he really hoped that they'd be on the same side. The white bandage on the NCIS team leader's hand seemed to suggest that he wasn't one to stand back and let others get mussed.

Gibbs let the elevator slide down all of half a level before stabbing the panic stop.

Don caught himself with a jerk. "What are you doing?"

Gibbs turned to face him. "My office."

"Your office?"

"My office." Gibbs deliberately leaned against the elevator wall. "What was your consultant working on? And why the hell do you use your brother as your consultant? I thought that the FBI had rules on nepotism."

Don chose to answer the second question first. "We do. My brother got his position through his own skills, by proving his worth to law enforcement. And," and Don leaned forward just slightly for emphasis, "his clearance is higher than yours and mine put together." Which might have been an exaggeration, but then again: it might not. Don only knew that Charlie had consulted at some of the highest levels, and that any travel outside of the country had to be cleared by the State Department before Charlie made his flight arrangements. Don went on the attack. "What are we doing here, Special Agent Gibbs, instead of tracking down leads?"

"We, Special Agent Eppes, are heading down to the Forensics lab."

With Goth-Girl? Oh, gawd. Give me Fleinhardt and Gatsbacher any day.

Gibbs kept talking. "I'll ask you again, Agent Eppes: what was your brother working on?"

"A lot of stuff, but nothing related to the FBI at the moment," Don told him. This was important information for the NCIS team leader to know. It ruled out a lot of possibilities, a lot of time-wasters. "He had an appointment at the Pentagon tomorrow—today," he corrected himself, looking at his watch and marveling that he still wasn't tired in the least. Remarkable what panic and adrenalin could do. "All of his current projects—to my knowledge—were related to academics, not crime or national security."

"What are his current projects?"

Don frowned. "He's an applied mathematician. He's working on something he calls Cognitive Emergence, and he's usually got a few pie in the sky proofs that he works on for various other scholars. Larry Fleinhardt at CalSci is one, and there are a few people at MIT and Stanford that he regularly corresponds with. That's co-authoring stuff, and not pertinent here. If somebody wanted the information out of those proofs, they'd be going after the primary author, not Charlie."

"The Cognitive Emergence stuff? What's that about?"

"Something about how people think," Don said, the frown deepening. "It's beyond me, but I don't think he's far enough along that anyone would want to hijack him for it. Even when it's finished, I don't think anyone besides the academic world will even care."

Gibbs grunted. "Maybe the CIA." He turned back to the point. "You said that he did some work for the NSA. What kind of work, Eppes?"

Don regarded the NCIS team leader. "Codes. Deciphering. That sort of thing. As far as I know," he added. "It fits, doesn't it?"

"It does," Gibbs agreed. "The NSA misplaced a message. Your brother is an expert at deciphering messages. You want to bet that there isn't a connection?"

"Not taking that bet," Don agreed grimly. "What do we do with that little piece of information?"

"Beats me." Gibbs looked away, tightening his lips. "Trying to track down everyone who attended your brother's lecture isn't going to happen; that's a dead end. All I know is that nobody knows what that missing code says, and that it means that something big is going down soon. We've got to decipher that code, and to do that we need both the code—and your brother." He pulled the panic button out of panic mode, and the elevator jerked itself back into motion. "Hopefully Abby will have something for us."