A/N: An event during the Tenth Doctor/Martha Jones era.

Primum non nocere fortasse

"I don't like the look of it" Martha Jones said as she examined the woman that lay unconscious on the bed. Her medical training had kicked in when the woman's husband came looking for help from the visitors. "She seemed fine the whole week that we've been here, but she developed a low fever late yesterday and doesn't want to wake up today. The same goes for Mrs. Stevens."

"You wanted to visit some early pioneers" a man said from across the room. "They didn't have access to modern medicines and equipment. Natural herbs and basic comfort are the best they can expect for some time. It's sad, but that's the way history works; I've seen it too many times to even keep track of it anymore." And the man had seen countless history; as a Time Lord, the man who called himself The Doctor tended to pay attention to patterns more than details, at least until the details hit him over the head.

"As may be, but it isn't any comfort right now and definitely not to her." She wiped the forehead of the woman named Kathrine Hatt and plumped the crudely stuffed pillow before replacing it beneath her head. She pulled the worn blankets down a little in an attempt to regulate the body temperature by allowing a little more of the cool air to circulate around her before she went to check on the other woman.

A head poked into the small one-room house. "How is she?" a bearded man asked.

"About the same, Mr. Hatt. I don't know what's wrong with your wife yet, but it's possible it will run its course within a day and she'll recover" Martha answered, trying to sound hopeful without really feeling it.

"Or as likely die" the man frowned. "I've told everyone from the start, I think this settlement is doomed; take it from Richard Hatt, we'll be lucky to be here in five years and not back in England with our tails tucked between our legs."

"It may not happen, Mr. Hatt" the Doctor reassured him. "And if it does, sometimes we have to fail before we learn how to succeed."

"Tell that to George Howe."

"I don't think we've met him, have we?" Martha asked.

"No, and you won't. He won't be learnin' how to succeed because he got killed by natives while crabbing but I guess his kid can learn how to be an orphan. All's you have to do is fail once..."

"Yes, look - you've got ninety men, seventeen women and eleven children here all helping each other. Fourteen families. Two of those children were born right here. I'm sure those relief supplies will be coming soon and then you'll look at things differently."

"Assuming Mr. White didn't sink on the way to England OR sink on the way back here OR was able to even get a ship. I tell you, when our ship showed up and found an empty fort with just a skeleton we should have kept going. I've half a mind that our pilot Senior Fernandez had motives to drop us off here and not continue on to Chesapeake; some say the Spaniards are behind it if it isn't fate that done it."

The Doctor went to the door and lowered his voice. "Mr. Hatt, can I speak with you outside a moment?" Richard agreed and stepped outside. "Thank you. Now I'm not saying that she can, but do you think it does any good for your wife right now if she can hear you talk like that? You need to be positive about these things, you know."

Richard pondered for a moment and then stuck his head inside. "Good thing we have some help to pull us through" he said before closing the door with the women inside where they couldn't hear. "I still think we're doomed" he spoke softly with a dead-level gaze at the Doctor.

...

"It's true, George was killed shortly after we got here but that was a misunderstanding" Thomas Seley explained later to the Doctor as they sat in his small house. "The good Lord knows there was some bad blood with the second attempt to settle here when, and I'm quite embarrassed to say this, some of the settlers burned down a nearby native village. Naturally, they attacked in retribution but that was in the past and now our group has managed to smooth things over with the natives. We've even had some of them visit our little village; you can see where we showed them our written language by putting their name on a fence post. Part of the trouble is it's been really dry this year and the crops have suffered for it; we've conserved the best we can and hopefully we'll get more rain next year. Otherwise we'll be forced to live off what the next supply ship brings."

"I noticed that you've used some stone along with wood to build."

"True. Ananias is skilled in tile and stonework and is trying to use some of the local materials. Let me tell you, the locals seemed completely shocked with the idea of making a building with stone. Our techniques are much ahead of theirs, understandably, and I think given the chance they'd probably use as many parts of our buildings for their own as possible."

"Do you think..." the Doctor started before being interrupted by Martha.

"Doctor? Three more people are sick now" she blurted out, somewhat out of breath.

"Same symptoms?"

"Yeah. Okay one moment, fever started and unconscious a little while after. They seem almost on the brink of waking up, but just can't."

"Probably exposed to Mrs. Hatt or Mrs. Stevens; let's move them into her house and that way they're all together. Mr. Seley, could you get us some help please? We need to get them and some type of bedding over there" the Doctor requested.

"I can probably arrange for them to be brought to the door, but I don't want any more of my people to go inside" Thomas stated flatly. "We can't afford to have everyone sick and something might happen if any healthy people go inside."

"Fine. Bring them to the door and we'll just drag them in" the Time Lord said with more than a bit of annoyance. "Martha, get Mr. Hatt to help you move things around to make room the best you can so we can turn it into an infirmary of sorts. I'll work with Mr. Seley to get the others there." Martha left their presence with Richard, who was still muttering about being doomed. "Let's go Mr. Seley, we've got work to do."

By the time they had moved the three new patients, five more had become sick.

Five hours later over half of the colonists were in the semi-comatose state. Martha was becoming exhausted moving from building to building checking on the patients. While none got worse, none got better either. Seley had ordered everyone to shelter in place in their own homes in an attempt to stem the tide of disease, but it was to no avail as everyone was sick by nightfall except Thomas and the ever dourer Richard Hatt.

The Doctor finally convinced Martha to rest for a short time to regain her strength while he himself started to pace about the small room nervously, unhappy that he had brought Martha here now. There were so many more places they could have gone instead...

"What are we going to do?" Martha asked wearily.

"Do? Nothing, I suppose. We didn't exactly bring a hospital with us, or the staff to run it. We're not supposed to be here anyway, but can you imagine the...the impact of bringing in help?" He looked worried and a little puzzled at the same time, almost distracted. "Wouldn't do, I'm afraid."

"So just leave them? If they don't wake up soon they'll die from dehydration even if starvation doesn't get them first. Can't we take at least some of them? What about that little baby, Virginia? Can you look at her and say 'Sorry, I guess it is your fate' and live with yourself?"

"Martha, anybody in the medical field knows that you lose patients; it's one of the most important rules. You lose people who aren't even patients. Everyone has a fate..." he said as he paused "...whether we accept it or not."

"Well, I haven't learned that part" she said as she stood, her anger giving her new energy. "I guess I just haven't seen enough people die yet!" she declared as she stormed out into the night. The Doctor started to follow, then thought better of it and instead sat and rubbed his temples. It was a hard lesson to learn; otherwise you didn't have the compassion to be in the profession in the first place.

As his thoughts wandered, they were brought back into focus as Martha burst back into the room as abruptly as she had left it. "Something is happening" she declared. She grabbed the Doctor by the hand and pulled him to his feet and led him out the door and to the Hatt's building. Inside, she pointed to Kathrine Hatt who still lay mostly asleep on the bed; however, her face was now marked by faint blue streaks. The Doctor looked at the next bed over and saw that Mrs. Stevens' face was beginning to show the same markings, even more faintly.

"What does it mean?" Martha asked. "We didn't come across any of this in our training at all."

The Doctor remained silent as he walked back and forth between the bed and the door several times before snapping his fingers and replying. "What it means is that I'm an idiot. I should have seen it, but it was the lack of streaks that threw me off."

"And what does that mean?"

"It means...that we've got some work to do. Let's get Mr's Seley and Hatt." In a burst of motion and a blur of trainers the Doctor was out the door and Martha had to hurry to catch up, barely managing to do so before they reached Seley's house. He rushed inside without knocking, and found Seley sitting in a chair with sweat on his brow.

"Just started" he said "so I guess I'm the next to go."

"And I'll be left all alone" Mr. Hatt muttered.

"Not yet" the Doctor admonished. "Mr. Seley, you've still got about an hour before you fall asleep. Care to help us evacuate everyone?"

"Evacuate? I thought you said your ship was about the size of a large box."

"It is...sort of. It's complicated. Mr. Hatt, if you're doomed what do you have to lose?"

Richard thought and was about to reply when he realized that he didn't really have anything else to lose. "Count me in."

"Great. I'll bring my ship up to each door and we'll use a litter to transport everyone inside one at a time."

"I have no idea what that means; sorry, it must be the fever. Just tell me what to do" Seley said as he rose slowly.

"I'll have time to explain more later. Allons-y!"

...

It was close, but Thomas Seley feel asleep before the last of the colonists were loaded into the TARDIS. It was Richard Hatt and the Doctor who carried Seley as the last patient into the control room, placing him in one of the few open spots left. Others lay along other passages further into the craft.

"I did as you said, but I'll take that explanation now" Richard said, slumping against a railing as he looked around. "If I'm going to be doomed, I'd like to know why."

The Doctor smiled for the first time in days. "No doom here, Mr. Hatt. Miss Jones and I are...travelers. This is my ship, which you've probably noticed is bigger on the inside."

"I don't care if it is or not."

Well, it took all kinds. "We travel not just around the world, but to different worlds too."

"A place is a place until it's different. Then it's still a place."

"Uh, so it is." No use muddying the waters mentioning time. "Well, Miss Jones and I visited another world recently that has a thing in the air that is nowhere else you go. The...people there are used to it, like if you get used to the smoke from a fireplace or the smell of a baker. But for someone who isn't used to it, well, they can get sick."

Martha was following along. The place had to be Arulty IV; they had spent a few days there after leaving England most recently. And there really wasn't any way to explain to Mr. Hatt the concept of immunology, disease transmission, antibiotics or even how a person could be a carrier and not get sick themselves.

"Okay, but I haven't been anywhere like that" Thomas countered.

"No; we, ah, brought the air to you accidentally when we came visiting. So the stuff in the air we brought made everyone sick" the Doctor explained.

"But I'm not sick."

"No Mr. Hatt, you most definitely are not. Certain people just don't get sick; I guess you're doomed to be well."

Richard mulled that over. "It's not very doomed, is it now?" he said, brightening somewhat. "But what about everyone else?" he asked, nodding in the direction of some of the sleeping colonists lying on the floor.

"We'll take them to a place they can get well, and then you'll all have to start over in another spot that...ah...doesn't have the bad air. But I'm afraid you won't be seeing anyone from the old world again; you are all going to someplace far away."

"That's alright; if I've got me Kathrine things won't be too bad" he said, actually smiling for a moment before getting up. He carefully made his way across the room to check on his wife.

"Doctor," Martha whispered "what changed your mind? What about that important rule that everyone 'has their fate' as you put it?"

"It's an important rule, and they do. But we caused the problem by being a carrier for the Arultian Fever that infected the population and I didn't figure it out until it was almost too late. But the most important rule above all is 'First Do No Harm'. Surely they at least teach that nowadays? Maybe?"

"Won't someone come back here and get sick?"

"No, the fever will only be active for about two more days by itself and then it will die out. After that's happened there'll be no risk of it spreading even when someone shows up after the storm that's coming in."

Before Martha could respond Mr. Hatt spoke up from across the room. "Are we going to go?"

"Absolutely! Let me set things in motion and we'll get everyone on their way." The Doctor picked his way over bodies to the TARDIS entrance and glanced out before the doors closed on a site of a fence post with the word 'CROATOAN' carved on it, near the entrance to the compound where Seley collapsed. Once closed, they left with a metallic whirling sound with only a square impression on the ground to mark where they'd been.

The End

A/N: Another fanciful explanation of what happened to the lost colony of Roanoke. Presumably the natives reused as many materials as they could when they came upon the abandoned colony.