Life couldn't get any better than this, McCoy thought. A quiet sickbay, plenty of free time, and Hope, safe and sound, filling every space in his life and in his heart. Long conversations over dinner and coffee, hot, sneaky kisses in the turbolift or even in his office, after watching her moving suggestively around sickbay or throwing him naughty looks across mess halls and briefing rooms, incredible nights and tender mornings in his quarters. His face hurt with the unaccustomed strain of constantly smiling, and his heart ached in the best of ways, whenever he had to wait for the next private moment with her.

He couldn't remember ever loving anyone more than Hope, and he was a hundred percent sure that he'd never been loved half as much before, warts and all. What she saw in him, he had no idea, couldn't grasp even though she was happy to list a thousand reasons whenever she saw the doubt in his eyes. He was, however, getting better at not questioning it too much, and trying to simply delight in his luck instead.

The psychologist in him suspected that the reason why they felt so deeply for each other lay in the life they led, the excitement, the danger, the fear of losing the other. But then he thought back to their first shore leave, the one that had finally brought them together. There hadn't been any excitement or fear there at all, unless maybe you counted a four-year-old falling into a pool. But helping an elderly couple across the beach or sharing a cake with a lovely teenage boy was hardly adventurous, not even at a stretch. And yet, he'd fallen a little more in love with Hope with every little gesture, every little thing she'd said or done during that glorious week.

No, life couldn't get any better than this. McCoy knew that. Just like he knew that good things didn't last. At least not in his world. Hope and he both had beaten death and disaster too many times. One of these days, they just had to run out of luck. Even a logical mind like Spock's, calculating the odds, would have to agree. Despite feeling on top of the world, or, given the doctor's disposition, more likely because of it, every happy thought was immediately followed by dread. Dread of this bliss ending somehow, and probably sooner rather than later. He couldn't help it, he was wired like that.

-x-x-x-x-x-

This time, disaster didn't strike, but crept up slowly. One day at a time. Jim had taken a landing party to a small, uninhabited planet. Just taking a few samples, having a look at the wildlife, nothing out of the ordinary. Everybody had been routinely checked and decontaminated on return, mission over. Or so they'd thought.

Three days later, Lt. Linden, a botanist and part of the recent landing party, arrived in sickbay with a stiff neck and a slight headache, asking for a pain reliever. McCoy didn't think much of it. Unlike other people, Jim, for instance, who were permanently stressed and tense, Linden rarely came to him for painkillers or with other medical issues. So he just briefly ran a tricorder over her and sent her off with a mild analgesic.

The next day she was back with a full-on migraine, something she'd never suffered from before, dark circles around her eyes, and a feverish hue to her cheeks. McCoy put her on a biobed for a thorough examination, but couldn't find anything wrong, apart from a slightly raised temperature. Nevertheless, he took blood samples, and put her under quarantine along with Kirk and the other members of the landing party as a precautionary measure.

Too late, as it turned out, even though Linden's first blood tests, according to which she should have been in excellent health, still didn't give any explanation. Only when McCoy drew some more blood and started over again, did he detect some kind of virus, unlike any he'd seen before. Going on to test Jim and the others, now that he knew exactly what he was looking for, he found them all infected by the same virus, even though none of them displayed any symptoms.

Cursing under his breath, mostly because he hadn't detected any infectious agents when he'd first checked the landing party after their return, he assembled a team and set up camp in the biolab, not intending to leave until he'd found a way to get the captain and the others out of quarantine again.

It was a good thing he was a devoted scientist as much as a healer. Although, when he'd first joined Starfleet, he'd somehow imagined he'd be mainly dealing with accidents or war injuries. Smashed bones, haemorrhaging wounds, burns, that kind of thing. Maybe the odd appendicitis or upset stomach. He'd certainly not expected to be dealing with new diseases all the time. But then, he'd always said that space was disease and danger wrapped in darkness and silence, hadn't he?

Hope, bless her, had immediately cancelled all her linguistic activities and come to help Chapel set up and get organised for having eight people quarantined at the same time. She'd also come to the lab several times, trying to counter the increasingly frustrated mood with her natural optimism. And it worked, for every time she left again, his team seemed to be more focused on their tasks, more determined to find a cure for their captain and the others.

Things took a turn for the worse, when Ghatak, a member of the science department and one of Spock's senior officers, didn't show up for his shift, and was found dead in his quarters, obviously surprised by a heart attack while having a shower. Meticulous as he was, McCoy checked him for the virus, too, and to his horror found that Ghatak had been infected, even though he hadn't been in the landing party.

That discovery, of course, immediately eliminated any hope of containing the virus, and McCoy quickly had himself and all sickbay and lab personnel tested. The result was devastating. They all tested positive, all but Hope, a silver lining that sent a feeling of disproportionate relief through his body. The next step, of course, was to have everybody aboard tested, and since Ghatak had neither been on the planet nor in sickbay recently, the odds in favour of finding more infected crew members throughout the ship scared the doctor.

To get her out of sickbay and away from himself and the other carriers, McCoy sent Hope on her way to collect blood samples from everyone, trusting that she understood the importance of wearing full protective gear for her own safety. The thought that he might not be able to hold or kiss her for a long time, if ever, briefly crossed his mind, making his blood run cold, but thankfully, there were a million other things to consider right now, keeping him from dwelling on that unwelcome thought.

By the time all blood samples had been tested, McCoy was no step closer to understanding what this nasty little virus actually did to the human body, let alone to finding a cure. All he knew was that the speed at which it spread was terrifying. This was one vicious little devil, and every single person aboard the Enterprise had tested positive. With two exceptions. Green-blooded Spock, which wasn't all that surprising, and Hope, which was a complete mystery to the doctor. McCoy was convinced it had something to do with her 20th century physiology, some immunity she had that had been lost over the centuries. But damn if he knew what it was.

McCoy was sorely tempted to put Hope under quarantine now, to keep her safe, but his reasonable doctor's brain convinced him of the absurdity of that. Instead, he settled on checking her for everything he could think of, hoping to find any clues as to her immunity. While he drew gallons of blood from her to examine, she mentioned feeling like Chekov at the time he'd been the only one in a landing party who hadn't mysteriously aged, having heard the full story from Pavel several times.

McCoy had, of course already thought of and checked for that, too. To no avail.

"Pavel had been too scared that time. So maybe I'm too happily in love?" Hope joked, and the doctor couldn't help smiling despite his growing frustration.

"But then I wouldn't be infected, either, love, would I?" he countered, raising an amused eyebrow and briefly caressing her cheek with the back of his hand.

"You might be as much in love as I am, Leonard," she said softly, and he could see that she was only half joking, "but with all your constant worrying, I'm afraid you can't even begin to imagine the blissful happiness I've found in you."

McCoy smiled and patted her cheek, closing his eyes for a moment to savour her words, and then told her to stay put for a couple of minutes to let her body recover. Maybe she was right, he'd give that theory another shot during his tests.

However, when more and more crew members came down with widely varying symptoms at an increasing rate, he gave up on analysing both the virus and Hope's blood. It had become pretty clear that the virus simply targeted the weakest organs in every human's body, and McCoy resorted to less refined methods, simply testing the effect of Hope's blood on the virus. The result was amazing. Hope's blood killed the virus. So, he started to work on a serum based on Hope's blood.

Then another man died. Again one of the older crew members, one of Scotty's trusted engineers and only ten years older than McCoy himself. The man had already undergone several kidney transplant surgeries and had died in his sleep.

Time was of the essence, and the doctor found that he couldn't waste any more on research and testing. All he could think of was that he had to come up with an effective serum before he, too, started to have symptoms that might render him unfit for work. Much as he trusted and admired Spock, Jim and the first officer were busy enough running the Enterprise with half the crew already unfit for duty. The Vulcan would hardly be able to supervise his team's progress on a serum on top of everything.

Deciding that it was time for more drastic actions, McCoy adapted the crude serum they had so far for his blood type and injected himself. It wasn't the first time he'd done something like this, either, he grinned to himself while he waited for the serum to show effect.

Although glad that he suffered none of the side effects he'd been half expecting, he soon realised that the serum had no effect on him at all. The virus lived on inside him, happily reproducing away. Not one to give up easily, McCoy injected himself two more times with ever increasing dosages, and almost cried with relief when it finally worked. Checking the results several times over, hardly believing that the virus had really been neutralised, he tried not to think of the amount of serum, and consequently Hope's blood, it had taken to cure just one person.

-x-x-x-x-x-

Jenny nearly kissed the doctor right there in the lab, in front of everyone, when he told her the good news, and was happy to donate more of her blood for the serum. Apparently, McCoy hadn't yet been able to determine what exactly it was that killed the virus, but for the time being seemed satisfied to know that it worked at all.

The doctor intended to treat the most urgent cases along with Kirk and the command crew next, and then take it from there, trying to get as much serum out of Jenny's blood as possible. He was hoping to use his own blood and that of the other cured crew members soon, too.

"With the amount of blood we've drawn from you, I need you to promise me to be good and not get up any time soon, love," he smiled as he personally set up the drip to compensate for her blood loss next to the biobed she was lying on. "I'll be pretty busy and won't be able to check on you. Can I trust you there?"

His tired eyes were filled with love and worry, and he pressed a gentle kiss on her forehead when no one was looking.

Jenny wanted to hold on to him, feel his arms around her, comfort him and be comforted. But of course, that wasn't an option. So she just nodded and waved him off to get on with the serum. And feeling, indeed, tired and a little woozy, she closed her eyes and drifted off to sleep.