"I gotta tell ya somethin', Spock."

That was how it began.

"But you can't tell Jim."

Fascinating.

Spock was sitting at the desk in his office behind Science Lab B. He had been doing some light research on a newly discovered species of feline that had recently been found in the jungles of Risa. It was a curious development; Risa had been inhabited by a space-faring race for several hundred years now, and the fact of such a discovery so late in their development was something of an aberration. Nevertheless, it had caught Spock's interest and he took a few minutes to read about it while the computer ran a simulation based on this morning's calculations.

It was nearing lunch time, and Spock intended to meet Nyota in the mess for tea and fruit. They were currently involved in a long-range stellar cartography assignment, so Spock had been excused from bridge duty so that he could be near the science departments in case they needed help with their scans and calculations. In fact, the bridge crew was working in short rotating shifts so that they could all have some down time to work on their personal projects while the ship was in a relatively safe situation.

Spock, because he kept a close eye on the senior staff and especially the science crew, knew that Leonard McCoy had not taken advantage of this. They had been on this schedule for two weeks, but the CMO had continued to work his regular shifts plus overtime in sickbay. Spock had noted this but kept his opinion to himself; he knew that humans required more rest than Vulcans, however he trusted McCoy to know his own limitations. Clearly, that trust was misplaced.

Spock had noted weeks ago that the doctor had lost weight, and because he had already received a large clue from his elder counterpart he decided to wait rather than confront him. By Spock's reckoning, McCoy by now would be suffering from fluctuating blood pressure and accompanying dizziness at the very least. However, given the pasty skin and slumped posture of the man who had just entered Spock's office, it was likely that he was also experiencing intense fatigue, lack of appetite, shortness of breath, excessive bleeding or bruising when injured, and perhaps a whole host of other symptoms.

Perhaps Spock had let this go too long after all. McCoy did indeed look like a dying man, and no doubt his condition had been exacerbated by the long hours he'd been working in spite of the fact that there were no emergencies, no landing parties and no pressing experiments. Clearly it had been an effort to distract himself from his own mortality. Humans had many great qualities, but their logic was often seriously flawed. Spock looked at the doctor blankly for a moment before opening a drawer in his desk and pulling out a tricorder.

"Have a seat, Doctor." Spock said as he stood, calibrating the device.

"Look, I don't have time for a tea party, Spock," McCoy grumbled, ignoring the chair that Spock was gesturing to. "I just need to inform my commanding officer of some personal details, and I need you to not tell Jim."

"I'm afraid I cannot make any promises with regards to the Captain." Spock mentally scowled at the numbers running across the tricorder's screen. "Do sit down," he said again.

"Yeah well Jim don't need to know this, and what the hell are you scannin' me for anyway?" McCoy's accent got thicker when he was agitated. This was a source of interest for Spock and great amusement for the Captain.

"You do not believe that your friend needs to know how ill you are?" Spock raised an eyebrow as McCoy's eyes widened. "Sit down, Doctor."

McCoy dropped into the seat at the corner of Spock's office, scowling at him.

"You know." he finally said. Ah, humans and their peculiar talent for stating the obvious.

"Indeed." Spock set the tricorder down, turning his back to McCoy and picking up a PADD. He had charted the doctor's possible progress and prognosis carefully. It was of course hypothetical, since he did not have access to the most correct data, however Spock had calculated that his estimates were 91.54% accurate.

"You ain't told Jim?" McCoy sounded a little shaky. Spock turned back to him, pulling up the chart he had created. It was not crucial, of course. The fact that McCoy was ambulatory and coherent meant that he was well within the parameters of safely enduring the cure's side effects. The tricorder data confirmed this.

"It was not my place to tell Jim, it was yours." Spock narrowed his eyes pointedly at the dark haired man.

McCoy sighed. "Fair enough. Look, he's under a lot of pressure. This could do a lot of damage. The kid don't need to know yet."

"Yet?" Spock tilted his head to one side ever so slightly, in such a manner that he knew reminded humans of domestic cats. Only Jim and Nyota had ever been so bold as to say so. "When did you believe he would need to know? When you are too weak to work? When you are hospitalized? Do you think that it will be less stressful for him then, to learn that you are on your deathbed?"

McCoy reddened and spluttered, gearing up for an argument, but Spock held up a hand.

"There is no need doctor." Spock opened another drawer. "I will not tell him the truth of your condition, provided you follow my instructions and cooperate. Do you understand?"

McCoy looked wary. "I dunno, cooperate with what?"

Spock turned back to the doctor and jabbed him viciously with the hypospray he had withdrawn from the desk drawer. It might have been retribution for all the times McCoy had punished Spock and Jim for their recklessness by treating them less than gently. But Vulcans were not a vengeful people, so it was merely a happy coincidence that he had been ordered to 'sneak up on' McCoy with the cure.

"Dammit, man, what the hell was that?" McCoy rubbed the side of his neck furiously, not having seen that coming. "I've already taken all the meds I can deal with today!"

"That, Doctor, was the cure." Spock maintained his indifference as he threw the hypospray into the trash and McCoy began to shout.

"Cure? Cure, my lily-white ass! You obviously don't know what's going on here, because there is no goddamn cure and I don't have time for any kinda false hope bullshit!"

"You believe I would do such a thing, if I were not certain?" Spock picked up his PADD, called up McCoy's work schedule, and deleted it. "I have tested it thoroughly. You will begin to experience some unpleasant side effects in half an hour or so."

"Bullshit!" McCoy was on his feet now, pacing back and forth. "I've got six months to live and here you are—"

"You have a lifetime to live, Doctor." Spock called up a different file and thrust the PADD at McCoy. "You may see the results of my tests yourself. However, I suggest you return to your quarters now and take a mild analgesic and something for nausea. You will wish to lie down for a few hours."

"I can't do that, I'm still on duty!" McCoy still sounded outraged, but he was looking over the data on the PADD with interest.

"In fact, you are not. I have removed you from the roster for the next two weeks." Spock picked up his comm and gestured McCoy toward the door even as the man protested having two weeks off. "Allow me to escort you to your quarters, Doctor, and I will answer any questions you have."

They exited Spock's office and made their way to a turbolift, where they rode silently up three decks. The CMO's quarters were much closer to sickbay than the other senior officers', so that he could arrive there quickly in emergencies. Fortunately it wasn't too far from the science labs, and they arrived at McCoy's door before the doctor became to exhausted.

"Some analgesic, Doctor." Spock reminded him as they entered, and McCoy grumbled his way to the bathroom and rummaged around in the medicine cabinet. Spock observed him swallow a handful of pills with a cup of water from the sink. He came back, still grumbling, and sat on the couch in the little living area.

"What the fuck, Spock?" he said, elbows on his knees, rubbing his forehead with one hand.

"Specify, Doctor." Spock took a step toward him, watching for any sign of a bad reaction. He remained standing at parade rest, hands behind his back, and attempted to look non-threatening. It wouldn't do for McCoy to throw him out at a time when he really needed to be monitored.

"Ok, just suppose that maybe it really was the cure for xenopolycythemia. Where the fuck did you get it?"

Spock had already conceded that he was going to have to reveal his source, or endure the doctor's wrath until the end of time. He had mentally rehearsed the whole conversation 13 times.

"You are aware of Jim's friend, Ambassador Selik."

"Your time travel expert, right."

"Indeed. He is not merely the foremost expert in the field, however. He is an experienced time-traveler himself."

McCoy looked up, eyes narrowed.

"Time-traveler."

"Yes." Spock nodded. "He has lived for over two hundred years and taken many trips, as I understand. He is not only a diplomat and an expert in temporal anomalies, but an astrophysicist, a computer programmer, a biologist, a starship Captain. A chess master."

McCoy chuckled. "Chess master," he repeated.

"What I am telling you is beyond classified. Only three people in the galaxy know the truth: myself, Selik and Jim. And Jim does not know all of what I am about to tell you. I trust that you will tell no one?"

"As long as you aren't going to tell Jim what I came to tell you, fine."

"A mutually beneficial agreement." Spock leaned forward imperceptibly; McCoy had begun to sweat. "Ambassador Selik does not belong to this time."

Spock believed that flabbergasted was the appropriate adjective for McCoy's expression here.

"What?" he breathed.

"Selik arrived here from the same universe as Nero, Doctor. He does not often give us specific information about his experiences, for fear that it may influence our behavior. In his own time he wrote the Temporal Prime Directive, which says that we may not interfere with any alternate timelines."

"Ok." McCoy wipes sweat from his face on his sleeve. "And in his universe, they have the cure for xenopolycythemia, I suppose?"

"Correct. In fact, Selik himself discovered the cure. He left me extensive notes on it, saying that although he did believe he should withhold most of his experiences from us, it was his discovery and he may dispense it to whomsoever he deems deserving."

"Pfft, bullshit. He's somehow decided that I'm deserving?" McCoy huffed in a breath, and Spock moved forward to grip his arm. The blue tunic was damp with sweat.

"Doctor, you appear to be in distress. Do lie down."

He thought McCoy would argue, but instead he came willingly as Spock guided him past the sleep partition and instructed him to remove his boots and shirts. He settled onto the bed while Spock moved to the replicator and dialed up a glass of cold water and a flimsy ice pack. He handed both to McCoy and seated himself in a chair by the bed.

"Are you in pain, Doctor?" he asked.

"Not much. Keep talking." McCoy pressed the ice pack to one of his wrists.

"Very well. Selik obviously believed you were deserving, or he would not have given me the formula."

"The formula?"

"Yes, on a data card, the last time he visited. He scanned you with his tricorder after you and the Captain fell asleep in the observation lounge. He left specific instructions for me to administer the cure to you without your permission, and then release the formula to Starfleet Medical in one year."

"Well goddamn, he thinks real highly of somebody who he's met twice!" McCoy was laughing weakly. "Decided I didn't need a choice in my own health care. Shit, Jim got to die once, why can't I have my turn?"

"He believed you would argue that there were other people who needed the cure more than you," Spock stood, heading for the bathroom. "and I trust his judgement and obey his orders explicitly."

"You do, do you?" McCoy muttered. Spock retrieved a towel and pressed it over the doctor's wet forehead. "Thanks."

"We are never too old to benefit from the wisdom of our elders, Doctor. And Ambassador Selik is... exceedingly elder."

McCoy chuckled again. "Well, maybe he knew me in another lifetime. Dammit, there are other people who need that cure. There are kids with this disease. I definitely would have argued."

"He did indeed have his own Leonard McCoy."

"Really?" The doctor was now shivering. Spock pulled a spare blanket from the foot of the bed over his shoulders.

"Yes. I am given to think that he assumed your personality would be much the same, especially after having met you in this universe. Have you eaten today, Doctor?"

"I had some coffee." McCoy said. "Not hungry much."

"Selik's instructions were for you to consume at least three thousand calories per day. Allow me to get you something from the replicator, or call your yeoman to bring a plate from the mess."

"Not now, Spock. Tell me about this cure."

"It is nearly one hundred percent effective. So long as the patient isn't actively dying, it is likely that they will survive if treated. The side effects of the original formula were harsh, but Selik spent many years adjusting it after discovery. You may have muscle aches, fever and chills, nausea and vertigo. You may also become dehydrated." Spock gestured to the still-full glass of water that McCoy had set aside. "Selik wishes for you to drink plenty of water and monitor your kidney function carefully. You are to remain off-duty for two full weeks, even if you feel as though you have recovered."

"Because he's a doctor now, is he?"

"He is many things. Would you prefer tea, or an electrolyte drink?"

"Whiskey."

"I'm afraid that alcohol will not help you stay hydrated, Doctor."

"Fine, whatever. Any other instructions from the old man?"

"He bade me reassure you that you are indeed worthy of the cure, as he was sure you would be very angry at having it forced upon you."

"Damn right." McCoy sniffed, still not drinking the water. "If I didn't feel so shitty I'd be kicking your ass right now."

"Of course, Doctor." Spock already knew that it was best to simply agree with the threats of bodily harm, as if the man wouldn't sustain more damage to his fist than Spock would to his face. "In his notes he informed me that by saving your life, he would be saving many thousands more who will benefit from your treatment someday."

"Sure, sure." the doctor muttered, obviously unconvinced.

"And he hopes that you will not be so upset that you refuse to see him when he visits next, however if you do he will be satisfied with the knowledge that you will live."

"We'll see about that."

"He wished for you to know that in his own time, you saved his life, his father's life and his friends' lives many times over, and he hopes that you will humor his foolish ways. If you do not agree with his logic, you are free to accuse him of going senile."

"Very thoughtful of him." Spock was unsure whether or not this was sarcasm. He was also unsure of whether or not he could actually repeat the last part of Selik's message with any kind of dignity. He cleared his throat.

"Selik would also like to offer you a 'virtual hug.' He claims he would offer you a real one, but he knows that you are a doctor and not a teddy bear."

McCoy was quiet for a long moment.

"Huh," he finally drawled. "Maybe he did know me."

"He asserts that you and he were great friends in another lifetime. And you have agreed to follow instructions. You must eat, and you must have something to drink before I leave you to rest." Spock stood. "I will get you anything you like, but you must eat something."

"Fine." McCoy groaned, annoyed. He moved to get up. "I'll get some stew from the—"

"You will stay where you are, and I will get it." Spock moved to the replicator as McCoy cursed at him. "Do you know the number?"

"Four-four-six-two-seven."

Spock returned a moment later with a bowl of chicken stew and a fresh glass of water. McCoy complained but finally ate quietly while Spock took out his comm unit and called the Captain.

"Doctor McCoy has contracted a strange flu, sir, and I have removed him from duty." Spock informed him. "He is in no danger, but requires rest and nourishment."

"I knew it!" Jim's voice came back over the line. "He looked like crap the other day at lunch, and he hardly ate anything."

"Indeed. I have escorted him to his quarters and put him to bed."

"Good. Tell him I'll check on him when my shift is up, and he better not pull any funny business."

"Funny business, sir?"

"Never mind, Spock. Just make sure he's settled and I'll come play nursemaid in a couple hours. Kirk out."

McCoy had struggled up and padded to the bathroom, muttering irritably and grabbing a clean pair of pajamas from his dresser on the way. Spock picked up the mostly empty bowl and glasses and returned them to the replicator while the doctor changed. He saw a particular juice blend on the screen that was apparently a favorite, so he ordered that and set it on the nightstand. He was pulling the comforter back when his unwilling patient reappeared.

"Jim says no funny business, Doctor." Spock informed him. He ushered McCoy into the bed and pulled the covers up.

"Too tired for funny business, Spock." the doctor replied. "I was comin' to tell you that I was getting' too anemic and shaky for a regular shift anymore."

Spock had to admit his curiosity. "You were overexerting yourself to begin with. And you expected that I would hide this from the Captain, how?"

"Dunno, you're the genius, not me. Would you—" he pointed at the desk, where a PADD and comm unit lay. Spock gathered them both and brought them over. "Thanks. So, in Selik's time, if he had his own McCoy, did he cure him too?"

"I assume so, though he gave no particular details of the circumstances." Spock sat back in the chair. "Why do you ask?"

"It's just... it's such a random trick of fate. There's no Selik on this ship, so if you and Jim hadn't known time-traveling Selik I would have died rather than been cured." McCoy looked tired, but he wasn't sweating or shivering now. He shifted uncomfortably under the blankets. "This universe's Selik probably died on Vulcan, or else he's a million light years from here."

"On the contrary, he isn't far at all, Doctor." Sometimes Spock worried about whether or not most humans were deliberately oblivious. "Do you know of no Vulcan scientists aboard, who are also computer programmers, chess masters and astrophysicists?"

McCoy stared for a second. Then another second.

Finally: "You ain't tellin' me that sweet old man is you. No fucking way."

"Two hundred years older, wiser, and perhaps, as he says, more foolish."

"Jesus, fuck." said McCoy. "How did... fuck!"

"Selik explained to us once that he believes that all universes tend to right themselves after an interruption." Spock steepled his fingers as he spoke, while McCoy continued to stare at him. "Nero came and disrupted our timeline, and yet somehow the Enterprise's crew came together the same as it did in Selik's timeline. A decade early, with a decade less experience, but still in the right place at the right time. I had done no research regarding your illness, and yet by the time you contracted it Selik was available with the treatment at hand."

"That's... Jesus." McCoy scrubbed his face with both hands. "How does that even happen?"

"I cannot say, although I suspect the Ambassador has his theories. You should sleep, Doctor, if you can."

"Not sleepy, just achy and tired. I should get up and finish my papework from this morning."

"You will not." Spock insisted. "You will rest here, whether or not you sleep." He picked up the PADD and touched the screen. "I will call up my notes on the tests I ran on the cure, perhaps you would like to review the results in detail. When you are stronger, Selik would no doubt appreciate your opinions on how the formula may be improved." He handed the device back. "I will finish your paperwork at your terminal and transfer any patients you have to other doctors."

Spock turned toward the desk. McCoy's voice stopped him. "Spock."

"Doctor?"

"Thank you." McCoy said. "Really."

Spock nodded once. "As we say, the honor is to serve."

McCoy fell asleep shortly thereafter, and Spock stayed to finish the doctor's work and divert everything else to the other medical staff. Two point three hours later he was still there, reading about the Risan felines on McCoy's terminal when Jim exploded into the room with a tray of chicken broth and ginger ale. McCoy startled awake immediately and swiped the PADD clear of the data it had been showing.

The Captain proceeded to fuss over McCoy, calling him 'Bones,' piling on more blankets and reprimanding him for not getting a flu vaccine. McCoy rolled his eyes and cursed at Jim, who ignored him and fluffed the pillows while muttering "calories, asshole." Spock made a mental note to send a message to Selik later, thanking him on the oblivious Captain's behalf. McCoy was right: Jim did not need to know.