A/N: If any of you have ever wanted evidence that I make up my stories on the fly as I go, this chapter is exhibit A. Everything in here are scenes that probably could have gone before the last few chapters, but I've written them to go together now. Because of this, this chapter seems really choppy and out of place, but hopefully it somehow flows along nicely. I should warn you, this chapter is a heavy dose of time travel theory, so put on your paradox hats and try to subdue temporal logic for as long as you dare! Enjoy!

Earlier that morning…

Merlin watched his older self quietly. The man was sitting at a small table near the far end of the room, under the window but not looking out of it, hands perched under his nose and face deep in thought. He hadn't moved much since he'd returned from the interview with Uther. Carefully, Merlin picked up a bottle of the enchanted medicine and approached the Older Merlin.

"You'll need to take this," He said. His other self grunted. "Of course, you'll need to eat something first. So you don't get sick." Another grunt. Merlin sighed uncomfortably. "Right." He scurried off and put together a breakfast tray and brought it back, with the medicine, over to his Older counterpart. He stood there for a moment, waiting to be acknowledged, but when nothing happened, he stepped forward and set the tray on the table in front of him. "I'll just leave this here, then." He went back over to what he'd been doing, sorting Gaius' newest shipment of herbs and putting away the elixirs that had been brewing overnight.

The small chambers were unbearably quiet, and even when the Older Merlin began to sullenly eat his breakfast, no one spoke. Arthur had left early that morning to see his younger self about gaining access to the archives, and Gaius was out on his morning rounds to his patients. Luckily, the morning proved to demand little medical attention. Gaius was back soon after the Older Merlin forced down his dose of medicine with a wince.

"Ah, good, you're up. How do you feel?" He asked the man. Older Merlin did not answer for a moment, but eventually shrugged and looked away. Gaius frowned at him, and then sent a look over at his ward past intensely set eyebrows. Merlin shrugged helplessly.

"He's been like this all morning," He told Gaius quietly when the physician came up next to him, "since he woke up. I don't know what's wrong with him." Gaius nodded and cast a worried look over at the warlock, who either didn't hear them or was pretending not to.

"Have you heard any word about Arthur – either of them?" Gaius changed the subject. Merlin shook his head.

"I woke up Prince Arthur earlier, did some chores, took out his laundry, but… when I came back he wasn't there. That's when I learned that Older Arthur had come to fetch him for something." He shrugged. "I can only imagine that they've been successful, since neither of them are back yet."

Gaius nodded. "Good. Well, go and finish whatever chores you have left in the castle, and come back here after." He looked over at Older Merlin. "I'll keep an eye on him." Merlin followed his gaze, sighed, and nodded. He left soon after, leaving the physician and his statue-like patient alone in the room. Gaius went to his routine of potion-making, comfortable in the silence but watching Merlin all the same. He'd noticed the warlock's quieter mood since returning from the interview, but it was growing steadily worse.

The situation must have been unnerving for the Younger Merlin, who had never actually had to interact with himself when he was buried in thought or depression, but Gaius recognized the signs. Merlin's mind was wrapped thoroughly around a problem, and he'd apparently come to a conclusion that was less than palatable. And he didn't want any of them to know. Just like he didn't want them to know about Morgana. Just like he hid his pain from the king, the prince. He wasn't talking. Just sitting there, brooding.

Gaius looked down at his work and tried not to be mad at him. It wasn't really working.

It was nearly dusk when the Arthurs came into Gaius' chambers, looking a great deal more comfortable around each other since the first time they'd spoken. Younger Arthur in particular looked rather excited about something.

"Gaius," King Arthur said, "we got into the archives, like I said we would,"

"Ah, yes," The physician brightened, "have you found anything about time travel?" Young Merlin perked up to listen, but his older self only spared a sideways glance from where he still sat at the window.

"No, not exactly, but we followed up on the one lead we had – the mention of Golcar in that book of yours…"

Gaius cut them off . "Oh, please don't tell me you wasted your time on that," He said, and both Arthurs looked a bit deflated. "I'm sorry, Arthur. I told you when you found that passage, the name sounded familiar? I finally remembered earlier why I knew it."

"And why is that?" King Arthur asked.

"Golcar is the name – surname, anyway – of two brothers. I only remember the name because they were the two very first patients I treated as Court Physician in Camelot."

The Arthurs stared, then began to frown, and then looked extremely, extremely confused. They glanced at each other. "You met them?" Prince Arthur asked. "You met Earnan and Eoran?"

"Yes!" Gaius brightened at the name, "Yes, those were their names." He frowned. "How do you know them?"

"We were looking for the name, as we said… we found them in the census records."

Gaius nodded. "It only makes sense. I'm sorry you went to all that trouble, though."

"Gaius," King Arthur sounded uneasy as he stared at the physician. "You couldn't have met them."

"Why do you say that?" The physician frowned. They could all feel the mounting tension in the air.

"The census records we found them in… Gaius, the Golcar brothers lived nearly two hundred and fifty years ago."

The silence was deafening.

"You're sure?" The physician's voice was weak.

"I looked through every record in the Five Kingdoms," Prince Arthur told him, "It's the first mention of Golcar I could find. The year 290. In Cenred's Kingdom."

Gaius was shaking his head. "That's… That's impossible. That's not possible. They said they were from Camelot."

King Arthur spoke up, "Um, Gaius, if I may… back then, Cenred's Kingdom was a part of Camelot." He paused. "They could have been telling the truth."

"But if they were telling the truth, how could they have possibly ended up here?"

"They couldn't have," Young Merlin spoke up for the first time. All eyes turned to him. "Unless they were attempting to travel through time, and they succeeded."

They all ate dinner together that night, talking about their discovery and what it could mean. All except for Older Merlin, who stayed resolutely in his seat, a tray of dinner and more medicine sitting untouched in front of him.

"What's wrong with him?" Prince Arthur asked, glancing over at the sorcerer.

Gaius sighed. I'm not sure. He's been… depressed like this ever since he returned from the interview yesterday evening. I don't know why."

"Has he been feeling alright?" King Arthur wanted to know.

"As far as I can tell, Sire. He's eaten at least a little, and taken the medication I've prescribed him. He looks healthy. Whatever it is that has him so sullen is not physical in nature."

Prince Merlin studied the other man curiously. He didn't think he'd ever seen Merlin depressed about anything. He glanced at the Younger Merlin, who met his eyes and blushed. The servant shrugged and went back to his meal.

"Since the interview, you say?"

"Yes."

"Strange. He seemed fine when I saw him there. He answered my father easily enough." And this seemed to interest Younger Merlin, who of course hadn't been allowed to sit in on the meeting.

"He could barely walk when he left here," King Arthur put in. His younger self looked somewhat surprised.

"Well he certainly managed just fine when he got to the throne room. Speaking of which, Gaius, I've been meaning to ask you something about Merlin's interview," He spooned in a mouthful a stew, and Gaius took the pause to look uneasy. "When he introduced himself to the council…" Arthur swallowed. "I wasn't aware that Merlin had a surname," He glanced at the younger Merlin, who frowned. Gaius paled. King Arthur tensed. The prince didn't seem to notice.

"But I don't," Merlin said.

"Well he said you do," Arthur jabbed a spoon in Older Merlin's direction. "He said his name was Merlin Emrys." Arthur's face made an odd expression as he sounded out the unfamiliar name. Beside him, King Arthur choked loudly on his dinner and slammed down his spoon.

"He did what?!"

Younger Arthur looked bewildered at his double's outburst. Gaius was pale. Merlin was squirming in his seat, sending accusatory glances at his Older self.

"His surname, he said it was Emrys." Arthur regarded himself with uneasiness and confusion. "Why, was it a lie? I didn't think Merlin had a family name…"

But King Arthur didn't say anything. He only stared, first at Arthur, and then at Older Merlin, who sat just as still as he had all morning by the window. He looked dead to world, but Arthur had known him long enough to know better. He glared harder. Eventually, he turned back to the group eating at the table. His expression was guarded and he didn't look at them as he spoke.

"Gaius, Merlin, Arthur… Would you give me a moment with him?" His tone was low and angry, and for a moment no one moved. "Alone."

"Right," Prince Arthur said uneasily, glancing at Older Merlin, who remained unaffected. "Merlin, come on. It's nearly dark and you've yet to clean up my room." He didn't sound like it really needed to be done, but it gave Merlin a reason to follow him as he left Gaius chambers. As he shut the door behind him, Merlin shot glances between his older self and the King. Gaius stood and looked for a moment like he was about to say something, but thought better of it and left quietly.

As soon as the door latch closed behind them, Arthur couldn't contain his anger.

"What the hell, Merlin?!" He yelled, and Merlin at least had the grace to flinch. "Good God, Merlin, what were you thinking?!" He stormed over to him. "Emrys? You told them? Are you insane? Morgana was there, Merlin!"

Merlin didn't move. Arthur clenched his jaw and thanked the stars above he didn't have his sword with him. He went around Merlin's table and planted his palms down on it to lean down in Merlin's face.

"Merlin bloody Emrys, I don't know what you are thinking right now, but you had better have a damn good explanation for this. You know how dangerous that information is in the wrong hands – Morgana, Merlin! My father! I don't care if it is your name, it could get us killed!" When Merlin didn't respond again, Arthur hit the table loudly, making Merlin's arms jerk back from it. "Say something, damnit!" Arthur waited for Merlin to meet his gaze, and when he did, his voice shook with restrained anger. "Merlin, why did you tell them?"

Merlin looked at him silently for a moment. "I'm sorry." He said, and looked down. "I had to know what it'd do."

"What it'd… Merlin, what are you talking about?"

The sorcerer sighed and rubbed the bridge of his nose. "Have a seat, Arthur." He waved at the chair across from him, and Arthur pulled it up to the table and tried to be patient.

"It's about this whole time travel thing," Merlin said, looking away from him. "No one knows how it works."

"The Golcar brothers seem to," Arthur said, slowly reining in his anger, "If we could find out-"

"How old were they?" Merlin interrupted. Arthur frowned.

"What?"

"In the census records you found, how old were they?"

Arthur's anger was beginning to melt into confusion. "Er… In their twenties, I think?"

"And this was the only mention of them that you found?"

"Well… the first mention, at least, working back from the present day."

"Then there was no mention of them after the date of 290 C.E." Merlin said. Arthur blinked. He hadn't thought of it that way.

"No, I suppose not. Why?"

"It's because they traveled forward in time, Arthur." Merlin said. "And they never got back to their original time."

It took a moment before Arthur could wrap his mind around that, but when he did, he shook his head. "Merlin, just because they didn't appear in the census again, that doesn't mean that-"

"But what if it does, Arthur?" Merlin turned to him. Arthur's eyes begged for an explanation, so Merlin took a deep breath, gathered his thoughts, and started over. "Arthur, the only things I know about time travel are all theories. Logic. And everyone I've ever spoken with on the subject all agree: if time travel is possible, travelling into past can bear only one of two consequences."

"Alright," Arthur nodded, trying to follow along.

"The first possibility is that by going into the past and changing things, a person could change the future – change the shape of destiny itself. The whole world could change, and when the traveler goes back to their own time, their future will be completely different than it was when they left." Arthur was looking rather worried.

"And the second?" He asked nervously.

"The second possibility is more complicated." Merlin clenched and unclenched a fist around his pantleg – a nervous habit of his. "By going into the past and tampering with events, a time traveler changes the future – but not of the same world. By changing the past, he creates not only a new future, but a new world."

Arthur frowned. "I don't understand."

"Tampering with the past, even in small ways, can bear huge consequences, Arthur. Like an archer. Even the smallest twitch of the bow arm, and the arrow lands metres off target, yes?"

"I follow,"

"Time is the same way. Change something just a little bit in the past, and in the future it could bear huge repercussions. Some believe that these repercussions would be so big, so irreconcilable that they would, in effect, create a whole new world, a new future, a new dimension."

"A new… world." Arthur said. "Merlin, I think you've lost me."

Merlin sighed, obviously unsure of how to explain. "Imagine a world, Arthur, a story. Now, if some of the characters from the end of that story were somehow transported back toward the beginning, and made to do it all over again, but with all of the original characters as well, the story would end up totally different, wouldn't it?"

"Yes…"

"But the original story was already written, you see. The new story can't just erase it. So it becomes a second story. Another book, or volume. Right beside the first, and similar, but very different. It's the very same with time, Arthur. By coming back in time to an earlier time in our lives, we may be creating new story; a new world. But it's not our world anymore. Our world is still out there somewhere, but the world we're in now, is the second world, the new world. Our own lives on repeat, but headed for a different path."

Arthur was following along this time, and he looked horrified.

"The longer we stay here, the more we interact, the more things we change, Arthur, the more we drift further and further away from our world. And the further we are away from it, the harder it is going to be to ever get back."

Arthur was blinking rapidly, trying to absorb and rationalize everything he'd just heard.

"But surely… surely there is a way… What if this isn't another world? What if it turns out to be like the first scenario you mentioned?"

Merlin's reply surprised him. "Do you remember it?"

Arthur frowned. "What?"

"Do you remember it? This? Arthur, if we were changing our own future – in our world right now, it would affect you and me even as we are here. We're from the future, a future we are reshaping as we speak. If we were able to change our own futures, we would feel it. Remember it, even as we change it."

"Like how?"

"Every day, you and I are interacting with our younger selves. You spent an entire day cooped up reading magic books with yourself. But tell me, do you remember that?"

"Merlin, it was this morning, of course I remember-"

"From his point of view, Arthur. Because you should."

Arthur looked at him oddly, and blinked, and then slowly began to understand. "No..." He said, revelation slowly gaining purchase on his face. "No, I… I don't."

"Exactly. Neither do I. That's why I introduced myself as Emrys. It'd been bothering me that I wasn't remembering anything that's been happening, but I thought maybe, it was just… lagging somehow. That if I did something bigger, something huge, it'd carry through to our own future faster so I would remember. No one in this time knows who Emrys is – yet. But if I reveal myself to be Emrys now, it will bring changes in the future, and I would remember it. But I don't." Arthur looked up to Merlin's face, and realized that he hadn't seen him look so scared in a long, long time. "We aren't changing our own futures, Arthur, which can only lead me to believe that we're changing someone else's future – Young Merlin, Young Arthur. We're changing the futures that they will grow up into. But they're not our futures. We're stuck in a world that's not ours, and I have no idea how we'll get back."

For a long time, they just stared. Eventually, although he wasn't sure he meant it, Arthur shook himself and told Merlin, "No. No, we'll find a way. We'll find out what these Golcar people studied, and what they did, how they… how they managed time travel. We will, Merlin. We will get back. But we're going to have to try." He swallowed. "Promise me you'll try, Merlin."

"You expected me not to?"

"It just… you've been brooding all day about this. But if it is true, what you're saying… I need your help."

"I know," Merlin said. "I'm just scared that I'll mess things up even further. But we need to work quickly, Arthur. The longer we stay here, the harder it'll be to get back."

And although neither of them mentioned Morgana, both of them were thinking about her separately. How did she manage time travel? What did she expect to accomplish? Where was she? And perhaps most importantly, would they be able to face her, should worst come to worst? Arthur glanced over at the bottle of medication that sat on the table where Merlin still hadn't touched it. He nudged it toward the sorcerer.

"If we are going to get out of here, we'll need you with your magic back."

Merlin actually laughed and took the bottled with a grimace. "Don't remind me." He drank the medicine and wondered if it would actually help.