Don felt horribly superfluous once they arrived back at the FBI headquarters. Robin took over, shouting orders to her team, hustling Charlie along on a stretcher and dragging Larry in her wake, kicking and protesting and limping all the way. Masked and gloved attendants swarmed over them. Don took refuge with the patients, sitting beside Colby, watching the circus with hollow eyes.

"Hey, Don. You find Charlie okay?" It was midnight, but Colby wasn't sleeping.

"Yeah. How're you doing?"

"Better." Colby tried not to shiver. "Close one, from what they're not saying. Rather not go through that again. There are those of us who won't ever be walking around again. Damn terrorists." He struggled to sit up, his face going white just from that minor exertion.

Don automatically reached to help. "Yeah." Don't want Charlie to go through it, either. May not have any choice in the matter, not now. Why'd I let him go on that damn camping trip?

"Think I'm going to go off of coffee for a while. Just a precaution, you understand. Kind of lost my taste for it." Colby reached for Don's arm. "Seriously, Don: Charlie? I gave him that damn plastic cup. It's my fault."

"It's not your fault." Don stared across the room where the activity was flying, wishing he could do something to help. There were too many people trying to do too many things to one small mathematician who, frighteningly enough, wasn't trying to object. That in itself was the scary part. Don couldn't wrench his eyes away from the scene. "If we're going to start assigning blame, give it to the terrorists."

"But—"

"No 'buts', Colby. Not your fault. End of subject. Listen, they're calling me. Got to go." Don rose in response to the Area Director's gesture. A.D. D'Angelo was in deep conversation with both Drs. Arthur and Marker.

"Aha! There you are!" Dr. Marker pounced. "What were you thinking of, letting that technician go on a camping trip? Do you understand that you may have loosed this plague across the entire nation? The entire planet? That kid's white count is skyrocketing! Do you know what that means?"

Don didn't. "What are you talking about? Robin?"

Robin was well-accustomed to calming her boss. She took hold of Marker's sleeve. "I can handle this part of it, Harry. We've got things under control."

"I want this man reprimanded," Marker bellowed at Area Director D'Angelo. The entire hospital ward could hear him and was listening hard, to judge by the number of winces that Don could see. Marker didn't care, didn't care that there were peopleill and dying in his presence. "I want that kid terminated, do you hear me? That's assuming that he lives! Of all the outlandish stunts to pull, Robin, this takes the cake. These L.A. types, nuttier than a fruitcake."

"Keep your voice down." Robin's own voice was sharper than usual. "There are sick people here, Harrison."

"I know there are sick people here, Robin! I'm in charge of them!"

"And right now they need you to be doing your job," Robin said. Don failed to see how Dr. Marker could miss the sarcasm, but the man managed it with a skill far beyond his supposed intelligence. "You're not needed down here, but there are things that we need from you." Like distance, for example.

Marker allowed himself to be pulled away. "Do they even realize what they've done? That they could have spread this contagion across the nation? Are they really that stupid?"

"Atlanta will want a full report, Harry," Robin told him, distracting her boss from his tirade with the enticing concept of another opportunity for him to suck up to his superiors. "They'll need to hear how you saved the day by contacting the nearby military bases to requisition those choppers and survival gear. Without that, we wouldn't have been able to get the situation under control nearly as quickly. He would have come in contact with the locals, and infected them. Atlanta needs to hear from you, Harry."

Marker brightened as the thought took hold. "Yes, they will, won't they? I'd better get started on it. They'll need that information immediately. Where's that secretary of mine? I'd better start dictating right away." He bustled off, already deep in thought. Don kept his eyes hooded, watching the man's back disappearing into the elevator, stifling the desire to throttle his neck. From the tight smile on Area Director D'Angelo's face, he felt the same way.

Robin sighed, shaking her head. "The person I really feel for is Jennifer, his assistant. That man goes through administrative assistants like we go through sterile gloves. The only good thing I can say about him is that he keeps the bean counters off my back, and that in itself is valuable. But if I had to put up with him any more than I do right now…"

Don had more serious concerns. "Robin? Skyrocketing white count?"

"An indication of infection," Robin explained. "There's a lot more to it, but that's the simplest way to describe it."

"And Charlie's is up?"

"It's climbing," Robin clarified carefully.

"That's bad. He's got it?"

Robin lifted her shoulders. "Too early to tell. On the positive side, we haven't had any more new cases of C-NO4 here in FBI headquarters since yesterday. I've caught up with my staff, and they've let me know the current status of the overall plague. Thanks to Charlie, we've contained it, interrupted the spread of the bacteria. There have been no further fatalities among those infected, and we're anticipating a slow but positive recovery for those affected. We think we've nailed down the protocol for beating this bug."

"Good to hear. What about Charlie? Robin, this is my brother we're talking about."

Robin pursed her lips. "I'm not sure. The tests for C-NO4 haven't come back yet. Another couple of hours."

"Another couple of hours? Robin—"

"I just don't know, Don." Robin looked away. "His core temperature is not yet back up to normal. He's suffering from hypothermia, and that's impacting the entire picture. I can't use fever as an indicator. With his WBC's climbing, I'm suspecting some sort of infection but it's too early to say what kind. It could be C-NO4, it could be the flu. With the dunk in the creek, it could just as easily be pneumonia."

"So he's got it." Shoot down one set of hopes. "What about Larry?"

"His white count is elevated but dropping," Robin said. "All very consistent with a viral influenza. Assuming he shows no symptoms, I expect to release him within twenty four hours, as soon as his C-NO4 titers come back negative. I doubt that he's infected. All Dr. Fleinhardt has now, according to the x-rays, is a badly sprained ankle. One of your people is getting some crutches and a splint for him. That's something we didn't bring with us," she added.

"Good. I'll talk with him, make sure that he understands not to discuss this with anyone." Don could at least do that. Can't do anything for my brother but I can tell his best friend not to blab about it.

Robin understood. "I'll take good care of him, Don. You know that."

"Don't worry about Dr. Marker," Area Director D'Angelo added, nodding at the elevator which had carried the man away before he could be murdered by the FBI agents on the spot. "That end of things will be taken care of. We've already got a flight back to Atlanta booked for him." He nodded at Robin. "And Dr. Arthur put in a call to Marker's superiors. His report won't go into the circular file, but the next best thing: it'll get filed where all of Marker's other reports have been filed. Apparently he's got a reputation, one that he knows nothing of." D'Angelo sniffed. "Our tax dollars at work." He grimaced. "But, on the bright side of things, it sounds like someone over at the CDC is interested in giving your brother a grant for that computer program of his. It sounds like he came up with a new approach, one the biostatisticians on staff hadn't thought of."

"I'll make sure that they call it by Charlie's name," Robin offered with a vicious grin. "That's the least I can do: make sure that Marker cringes every time someone mentions the 'Eppes Vector Analysis Program'. Oh, I'll enjoy that: give him the 'innocent stare' that reminds him that he made an ass of himself. And that I listened to him do it. 'Revenge is a dish best served cold'," she quoted, and cocked her head. "That's why I don't get rid of him, Don. Marker, I can control through his own foolishness. Why start fresh with another idiot that I'd have to break in?"

"Thanks." Don looked over at the cot containing his brother. The whole area was enclosed with plastic sheeting that was difficult to see through, the better to keep the infection inside and contained. Three nurses in blue scrubs were hovering around Charlie, poking and prodding, wearing masks and gloves. The covered form looked very still. Hypothermia, Robin had said. That caused his brother to be so limp and unresponsive. And still. Not moving.

That wasn't right. Charlie was never still.

Six o'clock in the morning. Not quite, still another two minutes to go. Five fifty-eight. Mustn't be inaccurate, not with his mathematical brother sleeping on the cot next to the chair that Don had dragged into place. Charlie would never forgive him for messing up numbers at his deathbed. Better not be your deathbed, buddy. The pole with the intravenous fluids dripping mesmerized Don, the drops falling one by one, the machine controlling their descent and whirring in an annoyingly steady rhythm.

One of the nurses had tossed Don a blanket to try to get comfortable, to try to sleep. Fat chance. The blanket had come in its own plastic gift-wrapping, sterilized after being used by someone. Who had used it, Don wondered. Marcy, the receptionist? She had already recovered and been released. Hers, fortunately, had been a mild case. She'd be back on duty, threatening anyone who tried to slip by the front guards, within the week, or so Robin had promised. One of the good promises.

Maybe Colby had used it, although Don doubted it. He'd still be using it now; the man was sleeping in the 'recovery' area several yards away. The recovering victims were slowly being isolated from the actively infected, and Colby was one of those recovering. He be out of work for a week or two, getting his strength back, and Robin had been concerned when she'd heard that he was a bachelor.

"Not to worry," Don had reassured her. "I'll put out the word to the clerical pool. He'll have more offers to be a houseguest than he can shake a stick at."

Six AM. For real, this time; the clock read 6:00 on the nose. All Don had to do was to assume was that the clock was accurate. He was sore, and everything ached; Don decided that sleeping in a chair the day after finishing with the flu himself was not the best way to treat his body. And then up half the night before, worrying over Colby. Then the take-down of the terrorist cell at the trucking company. Then the four hour night search and rescue for Charlie…Okay, Don Eppes had a right to be sore. This half-dozing state of sleep for a couple of hours wasn't going to cut it.

Charlie stirred, and Don came fully awake in a hurry.

"Don?"

"Right here, Charlie." Don couldn't resist; he smoothed back the tousled and damp dark curls away from Charlie's forehead, resenting the fact that the latex gloves came between him and his brother. Robin had insisted that he wear them, even though this thing supposedly could only be contracted through food. Body secretions, Robin had said. Can't be too careful. Not with this mutated piece of bacterial expletive deleted. Charlie's skin felt hot, even through the gloves. Mom used to do this, he thought. Mom took care of us when we were sick. Without the gloves. Wish you were here taking care of Charlie right now, Mom. We need you. Thirty plus years old, and still needing you.

"Feel awful." Charlie tried to open his eyes, blinked twice before managing it. He coughed, a harsh rattle in his throat. "Where—?"

"FBI headquarters. You—"

"I remember." Charlie groaned. He coughed again. "The whole thing, I remember. Tell me you didn't lose Larry's data."

Don ground his teeth. "You could have this terrorist plague, and all you can think about is some stupid experiment?"

"It's not an experiment, it was data collection—"

"Whatever. What were you thinking, going up there by yourself?" Don calmed himself. "What happened, Charlie? How did you end up in the water?"

"Don't shout," Charlie grumbled. "I'd think better with some acetaminophen. My head's killing me," he finished up hopefully.

"I'll get Robin. If she says yes, then you can."

"Robin." Charlie squinted his brows, trying to remember and making heavy weather of it. "Oh, yeah, the doc from the CDC. The smart one, not the one with an attitude. Now I remember. I met her, didn't I?"

"What happened on the mountain, Charlie? Is that when you got sick?" Don pulled his brother back to the topic at hand.

More frowning. Charlie struggled to sit up, not quite making it. "I didn't get sick, Don. A little high altitude sickness made me dizzy, and…" Charlie flopped heavily onto the bed. "Dammit, I dropped Larry's equipment. He's going to shoot me! He needed that—"

"We recovered it," Don interrupted. "It got hung up on a cliff, on a root sticking out. I thought for sure I was going to find you wrapped around the rocks below. What happened to you?"

Charlie closed his eyes. "I got dizzy, I dropped the backpack with Larry's equipment, and I fell. I slipped on some ice, I think. Boy, did I fall! Into some ravine nearby. It took me over an hour to find a way out, and then forever to get downhill to where I left the car. Then someone started shooting at me!" he added indignantly. "I'd ask you if that ever happened to you, but I'll bet that the answer would be yes. For simple math professors, the answer is supposed to be no." He shivered, pulling the covers up closer around his neck. Don automatically went to help. "Hey. You're wearing gloves."

"Right. You drank from a contaminated coffee cup, buddy. Robin's checking you out for our friendly neighborhood terrorist plague, as we speak. Remember? Colby gave you a cup of coffee two mornings ago, at the meeting, and you downed the whole thing."

"I did not!" Charlie glanced guiltily at Colby, still snoring in the corner. "I did, didn't I?"

"Yes, Charlie, you did." Finally getting through to the man. "Now, how do you feel?"

"Like crap." Charlie slunk further under the covers. "I've got it, don't I, Don?"

Another CalSci professor limped up, his gait awkward with the crutches under his arms. Charlie could barely recognize Larry with the mask over his face. Larry seated himself in the chair that Don offered, his leg stuck out awkwardly in front of him, a splint over the ankle prominently displayed. "I certainly hope not, Charles. I'll have you know that I have not been permitted to retrieve the data that you collected for me, to even see if it is intact given the untoward handling it has received. If it turns out that you have indeed contracted this artificially constructed ailment, then I too shall remain in quarantine until such time as I am no longer deemed a menace to society. Without my data, Dr. Eppes!" Larry looked annoyed enough to shoot someone. Belker, the dog, probably.

Another warm body slipped up behind Don, and put a gentle hand on the agent's shoulder, a warm body with a big grin and auburn hair tied back in a ponytail. "Then we'll simply have to remedy that situation, won't we, Dr. Fleinhardt?"

"Dr. Arthur?" Larry came alive, sitting up instead of slouching disgustedly. "You have news, I hope?"

"I have news."

"Which is?" Don held his breath.

"Nope."

Don fixed Robin with a stare, too scared to be hopeful. "What do you mean, 'nope'?"

"Just what I said. No C-NO4. No cholera. Given the current influenza epidemic conditions outside this building, isolation recommended but not required. Dr. Eppes, I expect to inflict twenty four hours of intravenous antibiotic therapy on you and then discharge you to home in the care of your brother or any other significant other that wants you. Dr. Fleinhardt, I am discharging you as of now to the care of your own physician. Follow up with that ankle if improvement is not noted within two days."

"Excellent!" Larry beamed. He struggled to his feet, grabbing the crutches. "My data, Don. Where is it?"

"He doesn't have it," Don repeated in wonderment. "Charlie, you hear that? You don't have the cholera thing." It didn't make sense. It was great, but it didn't make sense. He turned back to Robin. "But, how? He drank from the same cups as Colby. You found the bacteria on those cups. Other people got sick in the same way. Charlie was exposed, wasn't he?"

"Yes, he was indeed exposed," Robin nodded. "Cholera. Remarkable disease, almost wiped out Europe a couple of times throughout history. But for some as yet unknown reason, people with type A, B, and AB blood tend not to get it. Charlie, what type blood are you?"

"Uh…"

"Aren't you type A?" Don put in. "Something like that?"

"Honestly, I don't remember," Charlie confessed. "Are you saying that I didn't come down with this terrorist plague because I'm the wrong blood type?"

"Not the wrong type, but the right one," Robin corrected. "At least, that's the way I'd put it. Congratulations, Dr. Eppes, you don't have the plague."

Charlie blinked. "Don't take this the wrong way, Dr. Arthur, but I feel horrible. Not that I'm not grateful, but you're telling me I don't have this mutated germ of yours?" He coughed.

"That's right. No C-NO4. Not even the ordinary garden variety of cholera."

"Then—?" He coughed again, nearly doubling over.

"Pneumonia, Charlie." Robin smirked. "The garden variety aspiration pneumonia, brought on by trying to swallow most of a very cold body of water."

"Headquarters is like a department store after closing," Don observed to Colby, nabbing one of the skewered chicken vegetable appetizer things that his father made so well. Colby was looked better, Don decided. He was now wearing sweats instead of pajamas. As a matter of fact, he was up and walking. Two days ago, lying in bed was the man's activity level. Don approved of the improvement. He reached for another chicken skewer. "It's empty. One third is recovering from the terrorist thing, and another third is down with the flu. I've seen livelier morgues. These are good, Dad."

Alan Eppes slapped at his oldest son's hand and set the platter down on the coffee table. "Hands off, Donnie. These are for Charlie and Colby. They've been sick."

"What about me?" Don protested. "I was sick, too. I had the flu."

"You! You with the flu, you didn't come home. So you don't get any, tough guy."

Don snitched another one, pretending that his father hadn't made certain to keep the platter within arm's reach. "How about Robin? She didn't have the flu. You're giving her food."

"Lots of reasons, Donnie. Number one, she's a guest in our city. Number two, she took care of your brother and Colby."

"And number three? Is there a number three?"

"She's a doctor. Who wouldn't want to have a doctor in the family? I hope you're showing her a good time, Donnie. That's a hint, in case you didn't get it."

"Dad!" Don protested, trying not to redden. He tried changing the subject. "Thanks for taking care of Colby, Dad. I owe you one."

"You owe me a lot more than just one, young man." Alan looked at one of his two charges and smiled. "Or maybe not. This house hasn't had so much life in years. I kind of like having kids around again."

"And I appreciate this, Mr. Eppes," Colby said sincerely.

"Dad, we're not kids," Charlie objected, leading Robin down the stairs and coming into earshot. He coughed again, the sound harsh in the air. Don winced, even though the cough sounded better than it had. Charlie looked better, too; not quite so pale as he did just three days ago. Robin had just finished checking him out for the last time.

"To me, you'll always be kids."

Don grinned directly at Colby. "And you've been having a sleepover. Don't stay up too late, boys."

"Late? Right now, eight o'clock rolls around and I'm out like a light," Colby complained. "In case I haven't said it before, Mr. Eppes, thanks again for taking me in. And thanks, doc, for all you did." I wouldn't be here if you hadn't hung in the air, unspoken.

"Just doing my job," Robin said lightly. "Dr. Marker has already flown back to Atlanta, so I have just a little cleaning up to do and then I'll have to follow. I've already closed down the hospital in the basement of the FBI and these two here are among my last two patients. My flight leaves tonight."

"So soon?" Don said, dismayed. "I was hoping to show you around L.A. It's not as though you had much chance to see the place. You can't stay another day and relax?"

Robin smiled at him. "I'll take a rain check, Don, if you don't mind. But there is one thing I would like to do in the time I have left here."

"Name it."

"You remember I told you that math was one of my undergraduate majors?"

"I remember," Don lied with a straight face.

Robin glanced at her watch. "I have two hours before I have to get to LAX." She turned to Charlie. "Dr. Eppes, would you do me the very great honor of explaining the Eppes Convergence?"

Charlie beamed. All the lines in his face, leftover from the pneumonia, vanished. "Come into my office. The garage," he explained. "It's easier if you see it written down."

"Wow! How many people get their own private tutoring session from one of the world's greats?"

The pair was off like a shot.

Don stared after them. "I offer her L.A., and she wants the Eppes Convergence?" He shook his head.

"What are you complaining about?" his father grumbled. "She turned down my famous chicken shish-ka-bobs."

Colby reached over and snagged another one, popping it into his mouth with a contented sigh. He relaxed back onto the sofa. "All the more for me, sir."