Disclaimer: YES! YES! ALL MINE! Huh? Er....Sorry, Mr. JJ, sir, won't happen again...

AND ONE TIME IT PROBABLY SAVED THEM

It's the night McCoy finally diagnoses Chekov's painful rash and high fever as measles, old-Earth style measles, and though it's almost midnight Jim is still up, worried and tired. He's been writing a draft of the letter he doesn't want to send, and hating that it would be the first one he ever wrote as this ship's Captain.

"It's better that he's got it young, Jim." Bones tells him in a low voice, leaning against the far wall of his office. "If he was just a couple years older, the encephalitis could've killed him before I figured this damn thing out."

"Encephalitis-?"

"Brain inflammation, common complication with adults. It comes on fast, and I wasn't looking for it – Jesus, he's lucky M'Benga recognized the Koplik spots on his cheek. It probably means those colonists down on Telos III are carriers. Damn primitive medicine…" He rubs one hand wearily across his eyes. It's been four days since their navigator started running a fever he couldn't knock out, two since Bones has slept. For a while he thought the coughing and sneezing and fever might be some deadly alien pathogen that he was going to have to discover in a post-mortem.

"Measles is really contagious, right?" Jim vaguely remembers from old history classes, but the disease was supposed to be extinct nowadays, so rare that vaccinations were hardly ever administered. In fact, the medical database contains only a paragraph on the subject, and the virus map hadn't even been programmed into the ship's computers for identification, which was why it took this long to diagnose Chekov in the first place.

"Yeah, I've got Spock synthesizing the antibodies now and I'll be dosing the crew tomorrow morning. I've already put out an alert to avoid sexual contact or sharing food, and anyone with a cough or runny nose should be reporting to Sickbay now so I can head it off. Scotty's replicating me some Vitamin A tablets to hand out, try and boost people's immune systems until the vaccine takes effect."

Jim leans back in his chair, mentally going over what he needs to do to make sure they don't fall apart if the measles spreads. Duty rosters, med-checks, shift adjustments, quarantine rooms – "How sick is Chekov?"

"Pretty bad, but stable. I mean, he's uncomfortable as hell, and his temperature's all over the place. Sulu's with him until I can inoculate the nurses."

"Sulu's already immune?"

Bones gives him a wan smile. "Had me give him the available vaccine this afternoon with a booster to make it work faster. He's been translating." At this, Jim cocks an inquisitive eyebrow and the doctor explains "Pavel's fever is up to 40 Celsius, he's delirious. Maybe one out of every twenty words is in English at this point, so Sulu's talking to him and keeping us updated. Chapel thinks it's adorable." He adds with a snort of disdain.

Over the next few hours, Jim marvels at the efficiency with which the medical staff immunizes the crew, the responsibility of officers who walk into Sickbay 'just in case' their sneezes are something more than the dry air, and the energy of his bridge team, compensating for their absent helmsmen. They get by on hastily-warmed soup, and strong coffee, and the occasional Pop-Tart from the emergency stash. He's quietly pleased at how Sulu refuses to leave his friend's bedside, and surprised by Spock's arrival with some kind of Vulcan lotion that soothes the painful rash enough for Chekov to sleep. And even when the kid develops a bad ear infection, apparently a common complication with juvenile cases, he's reminded by Bones that it could've gone so much worse if he was really post-pubescent – corneal scarring, or encephalitis, or pneumonia.

The fact that they practically live in dorms, and measles is airborne with a 90% communicability rate, means they get another fifteen cases before the week is out, wreaking havoc with the duty roster. Thing is, they're all from the Ensigns' barracks, and they're all under 21, and McCoy is thanking whatever gods are out there that it wasn't the older staff. Jim realizes that if they'd been any normal starship crew, they might've had actual deaths – even for all their technology, they still can't cure measles, just treat the symptoms – and that somehow, they've finally caught a break.

"They're really young." He says, looking through a window into the darkened quarantine room. Sulu is talking quietly to Chekov, and Chapel is moving efficiently from patient to patient with more of that funky blue lotion, and the row of gangly, tired, feverish ensigns just look like children put down for a nap.

"We're all really young." McCoy reminds him, letting himself see a twenty-five-year-old kid with a starship full of responsibilities, an ego the size of the Laurentian system, and enough vulnerability to let his best friend give him a hug on a late night in Sickbay.

"But we're okay." he says into Bones' shoulder, squeezing tight and looking for reassurance.

McCoy tightens his grip. "Yeah, Jim." Because so long as they've got this strange, brilliant, determined crew together, age doesn't mean a damn thing.

And that is all. Hope ya got a few laughs.