Castiel woke up, which was still in itself an odd sensation, to an odd buzzing sound focused somewhere over his chest. Without opening his eyes, he reached out a hand to grab the buzzing object. It was metal, cylindrical, and buzzed in his hand for another second before it was pulled out of his grasp.
Above him, a man's voice laughed. "Hey now, leave that be. I'm helping you here."
For a long, foolish second, Castiel wished that he had heard a different voice. That someone else was helping him.
"Ah, Martha," the man above him called out. "Could you bring that doohickey over? No, not that one, on the left... your other left. Yeah, that one. Thanks."
But Dean was as good as dead. Castiel opened his eyes and sat up, identifying this new location. Pale walls, a metal table under his body, shelves of medical equipment - this looked something like a hospital room. Strange, though. Something about it all felt very... odd.
The man who had been working on him clucked his tongue and shoved at Castiel's chest, but he didn't budge. He hissed reflexively; the skin he'd carved the sigil into was still sore and sensitive.
"Doctor!" the woman - Martha - scolded. "He's already hurt; you don't need to exacerbate the problem."
The doctor removed his hand. "Sorry."
Martha shoved a strange machine into his hands. "Here's your doohickey." The doctor turned it around in his hands, twisting some knobs and pulling levers. Martha turned to Castiel with a strange smile on her face, warm yet hesitant. She placed a stethoscope against his chest, which did not so much sting as calm. "So... you're awake now," she said.
Castiel looked down at his body. "I am."
"You feeling any better?"
His hands clenched into fists. "No."
Martha winced. "Right. Sorry." She lifted her stethoscope away from his chest, glancing awkwardly at the doctor, who was preoccupied with his "doohicky". "Look," she said in a low voice, "I know it's not my place to ask, but - is your side losing?" The last word was in a whisper so low it could almost not be heard at all.
Castiel frowned at her. "My... side?"
"You know," she whispered, pointing up.
Ah. It seemed they only partly understood his situation. "If that was my side, I would not be needing your doctor's assistance."
Her eyes widened, and she stepped back. "Then - "
"No. There is a third side to this fight." When Martha looked confused, he nodded at her. "You. Humanity."
"Oh, I like you," the doctor said, jumping in with his doohicky. "Fighting on the human side, always an indicator of a good man. Well," he amended, sticking the doohicky on the central mark of the sigil, "of a good being." After a moment, he pulled the doohicky away, saying, "All done!"
And, indeed, when Castiel looked down at his chest, it was healed. Not to the standards he used to have for healing - there were still scarred regions of skin where the carvings once were - but far more healed than he could have managed in such a short time. He touched the skin, gently, and found it was no longer sore. "How - "
"Oh, this? It's just a metabolism enhancer. Wouldn't do much for a human, they take so very long to heal, but for you? It gave you the boost you needed to heal yourself."
"I see." Castiel stared up at the doctor. "And what does it do for you, doctor?"
The doctor raised his eyebrows and grinned, pointing at Castiel again. "You see? I was right to like you, you're clever. And, since you asked, it does about the same for me as it does you. Leaves me absolutely starving, though - uses up a lot of energy."
Castiel's stomach growled. In the face of both the doctor and Martha's grins, he couldn't help but smile a little himself, if more self-deprecatingly. "I suppose I could... go for a burger," he admitted.
The doctor's grin spread wider. "Alright, then! What say we go find a McDonalds?" He left the room, talking about the longevity of capitalism and brand names, leaving Martha to assist Castiel off the metal examination table.
"Here you go, then," she said once he was standing on his own feet. "Can you walk?"
"I'll be fine," Castiel said, intending to leave immediately. What he found, though, was that he could not simply find a location on Earth. He rubbed a hand across the bridge of his nose. He had been right before; there was something off about this place. "Can you lead me out of here?"
"Sure!" She left the room, and with a glance back to make sure Castiel was following, led him down a hall. She turned at a corner he didn't see at first, and immediately made another turn. And another, and a third. Castiel would have been sure that they were going in circles, if not for the fact that each door they passed was distinct and different from the last.
"What is this place?" he asked.
"The TARDIS," Martha answered, turning around. "I know, you feel like you've gone around backwards, haven't you? It's like a giant maze sometimes, I swear."
"It's not that," Castiel said slowly, peering closer at the walls of the "TARDIS". "It's not temporally stable. I can't sense the outside world. I think it's because I can't tell when I should be sensing it."
"You can time-travel?"
"Yes. It's not a commonly used ability, but it allows me some sense of when things are not right." He glanced at Martha. "Such as you. You aren't from this year. You're from a nearby year, but just far enough away to be noticeable."
Martha shrugged, smiling. "You got me. I'm from 2008 - the Doctor and I have been traveling together for a few months, across time and space."
"In this... TARDIS?" An idea was forming in Castiel's head - an absolutely terrible idea, but one he couldn't quite avoid thinking. This ship could travel through time. He wouldn't have to kill himself to make a change in the past. Nothing big, nothing the angels or demons would notice, but something small enough to make a difference. Something like...
"Hey!" the doctor called out from some other part of the TARDIS. "You lot coming or not?"
Martha grabbed Castiel's hand and squeezed. "Come on, then," she said. "Bet you're still starving." She pulled on his arm, and Castiel found himself following, despite his normally immobile nature. "And while we're eating," she added, "you can tell us all about this Apocalypse of yours. I know you don't want us to, but we can help. It's what we do. What he does."
She smiled, warm and gentle, and though he was the only person she could have been smiling at, he got the feeling she wasn't thinking of him.