This is a one-shot I wrote some time ago and had posted at a British Dr Who archive.
He simply appeared one day. In the distance, atop the gentle rise of the knoll between her homestead and the eastern hoizon. Actually, it was a tree that simply appeared. Where there hadn't been one befre. HE had simply walked out of it.
The woman paused in her work of turning over the soil in the herb garden to watch him stagger toward her. When he finally fell and didn't get up, she dropped her shovel, brushed the dirt from her hands and mached over to him. He was a sight! Bloody, sooty, clothing torn and oddly singed... Hard labor in her own fields had made the woman strong. She didn't give a second thought to kneeling and pushing/pulling/tugging the unresponsive form until she had his arms over her shoulders and body draped down her back like a cloak. But he was heavy despite he wasn't too terribly large, but determination won out over the few false starts and once on her feet, she finished his staggering journey to her small cottage.
--
She was standing over him when he finally roused; her hands on her hips, lips pursed in uncertain curiosity. "You heal right fast," she said by way of greeting.
"Apparently with your help," the man replied.
She simply nodded and went on studying the angular lines of her guest's face. It was not really an ugly face, rather, aristrocratic, though her language lacked that term. "Are you thirsty? Hungry?"
The man looked startled for a moment. Then replied in the affirmative.
--
The man was regaining his strength far more quickly than a normal person would. But he did not seem overly eager to leave. In fact, it seemed to the woman as she silently watched the man sleeping beside her, in whose arms she'd spent the last several nights, that he'd found a peace he was loathe to abandon. She watched him awaken slowly, as a man without worries...
She set out the usual hearty breakfast of eggs and biscuits, and, now that they were ripe, a bowl of sweet red berries all to be enjoyed with a hearty herbal brew that would take the chill out of the morning. The man came inside after his morning ablutions to take his place at the table. He didn't look at her directly, staring at the feast, his face a collection of a myriad of emotions.
"I have to leave," he announced abruptly. "I'm leaving."
"I know. Why?"
He laughed shortly. "There's a Universe out there that I intend to conquer."
The woman set her hands on her hips, head tilted almost daintily to one side. "Why?"
The man blinked at the unexpected question. It made him hesitate. "Well, I...It's there for the taking. Certainly the rest of them have done nothing better with it!" The words were angry, the voice bitter.
"Hurt you a lot, I see."
"First I intend to finally kill the Doctor! I should have done ages ago, his meddling is too much!"
"Good luck."
"You don't believe me."
She shrugged.
"Believe this, I've killed a lot of beings --"
"-- to get where you are today? Is it so bad here?"
"I'd make a very poor husband and father," he tried to sound offhand.
"Do you enjoy killing?"
"Of course not! But they get in my way. They have to go." he paused as realization settled. "You said 'I know.' " It would have been an accusation but for the surprise in his voice.
"I've seen it coming."
"You're not going to make a scene, beg me to stay--?"
"No. it wouldn't change your mind and I don't want to be one of those 'in your way.' " The last she added wryly. "Anyway, I never expected you to stay."
"You... You did save my life." Good thing too, he had no more regenerations left at that! "I don't generally kill someone I owe my life to."
"You should have a good breakfast before you leave." She grabbed a couple biscuits and headed outside. "I'll be in the house garden."
"I'm not one for goodbyes."
"I know. That's why I'll be outside. Just leave the dishes. I'll get to them later."
--
It was five years later when the tree reappeared. The woman was tending the herb garden again, this time with the enthusiastic but not particularily effective help of her dark haired daughter. She smiled down at the child who beamed back, secure in the knowledge that she was 'helping mommy.'
The man did not stay long. Only long enough to present the child with a soft stuffed toy... And to hear the woman's claim that he had already given her the best gift possible...
The woman never saw him again. She did wonder, from time to time, if he'd managed to conquer the universe. It he had, it certainly hadn't changed anything in her universe. But then, he had conquered that without any effort at all.