Note: Mild spoilers up to and including episode 1x10 "The Moment of Truth"

An Unexpected Detour

They were only meant to be gone for a few hours. Just Arthur and Merlin, without the usual entourage of knights, away from the castle for an afternoon of hunting. But despite Arthur's best intentions, it wasn't a very pleasant afternoon. There was a curious lack of game and Merlin was even more useless than usual, startling at every noise in the woods and constantly bumping into Arthur because he was too busy peering anxiously through the trees to pay any attention to where he was going.

After another dismal hour, Arthur sighed in disgust and told Merlin to gather their supplies, deciding to head back early. They had just reached the path that led out of the woods and towards the castle when a cloaked figure emerged from the trees. Arthur didn't have time to draw his sword, he barely had time to realise that they were being ambushed by a sorcerer before a ball of fire was sent hurtling towards him.

And then suddenly Merlin was there, launching himself onto Arthur and knocking him to the ground. Arthur looked up into Merlin's eyes and they flashed gold, and that wasn't right at all because the fire was coming closer but it was at Merlin's back. Then the fire rolled backwards and the sorcerer gave a shout as he was engulfed in flames, and suddenly the world vanished around them.

The sorcerer, the forest, and the cloudy grey sky all disappeared in an instant – or rather, Arthur and Merlin disappeared, finding themselves abruptly transported to a sunlit vale.

Arthur looked up at Merlin again and saw that it hadn't been a trick of the firelight; his eyes really had turned gold and were only just now returning to their normal blue. He looked just as surprised by his surroundings as Arthur did, and Arthur wondered if that should make him feel better.

It didn't.

"Get off," he said, roughly pushing Merlin off his chest so that he fell to the ground in an awkward heap. Arthur sat up and looked around. There were a few trees scattered about, but there wasn't a forest for miles around. Arthur had never seen this place before. He didn't even know if he was still in his own kingdom.

Out of the corner of his eye Arthur could see Merlin sitting up, but he couldn't bring himself to turn and look at him.

A few moments passed in tense silence before Merlin spoke in an uncertain voice. "Arthur?"

"Don't," Arthur replied angrily.

Beside him Merlin shifted, moving so that he was directly in Arthur's line of vision. He reached for Arthur's arm. "Arthur, please-"

"Don't," Arthur repeated, wrenching his arm away from Merlin's grasp. "Just don't. I won't listen to any more of your lies."

Merlin drew back as sharply as if he'd been struck, and the expression on his face was so full of hurt that Arthur had to look away. Merlin's satchel had landed nearby, and Arthur dug around in it now until he found their empty waterskin. He could hear the sound of running water; it didn't sound like much more than a stream, but it was close, and right now Arthur just wanted to be away from Merlin.

Soon enough, Arthur found himself standing at the edge of a brook. He spent a moment contemplating the stream before deciding that Merlin had probably not transported them to a place with poisonous water. Besides, he was thirsty. Arthur filled the waterskin and took a long drink before he sat on the rocky shore and closed his eyes, listening to the sound of the water rushing past and feeling the sun shining on his face.

Merlin was a sorcerer. Now that Arthur knew it, now that he had witnessed Merlin's magic with his own eyes, he wondered how he had been so stupid. The signs had been there all along. All those mysterious circumstances that seemed to follow Merlin around – the snakes on Valiant's shield that just happened to appear without being summoned, the sudden disappearance of Sophia and her father, the windstorm in Ealdor. The ball of light that guided Arthur away from the spiders and out of the cave. How had he not seen them for what they were?

Arthur sighed. He didn't know what to think or what to do. Everything he'd ever been taught told him that magic was wrong and something to fear. But this was Merlin, and Arthur wasn't afraid of him, even after all that he'd seen today. How could he be? Merlin was infuriatingly incompetent, hopelessly awkward, and unbearably slow. And he had apparently saved Arthur's life a dozen times or more since coming to Camelot, a fact that Arthur was not going to think about at all.

He sighed again.

Arthur didn't know how long he lingered by the stream, but at last he refilled the waterskin and headed back to Merlin. He was right where Arthur had left him, sitting with his knees drawn up to his chest and his head bowed, staring intently at his feet. He looked small and scared and alone, and Arthur absolutely hated seeing him like that.

"Here," he said gruffly, nudging the top of Merlin's head with the waterskin. "Drink up."

Merlin lifted his face, his eyes betraying his wariness and confusion, and Arthur couldn't help but look away, his eyes shifting to focus on Merlin's shoulder instead. After a brief hesitation Merlin reached for the water and at that movement, Arthur caught sight of something on Merlin's back. Before Merlin could drink, Arthur dropped down beside him and stilled him with a hand to the shoulder.

There was a long stripe across Merlin's back, like a – like a burn, Arthur realised, searing right through the soft suede of the jacket to the blue shirt underneath. He must have been hit by the sorcerer's fire, and something like worry and fear made Arthur's heart clench.

"Take this off," he said, tugging at Merlin's collar. When Merlin only looked at him oddly, Arthur rolled his eyes and removed the jacket himself, carelessly flinging it aside. The blue shirt was only slightly singed but Arthur quickly pulled it up as well.

Underneath Merlin's skin was white and smooth and unblemished, but Arthur placed his hand on Merlin's back nonetheless. As he knew well, magic didn't always leave a mark.

Arthur watched Merlin's face closely as he pressed his hand between his shoulder blades, right where the fire had hit, but Merlin just looked at Arthur steadily in return, showing no sign of discomfort.

Arthur let Merlin's shirt drop. "You'll live," he said.

"I've had worse," Merlin replied before looking away, as if sensing that it was probably not very wise to mention his past experiences with magic in front of Arthur. He took a sip of the water before turning his jacket over in his lap, unconsciously fingering the scorch mark.

Arthur watched him for a moment. "What happened back there?" he asked. "One moment we were in the forest, and the next-" He gestured at the valley around them.

Merlin shrugged. "I don't know," he said. "I don't even know where we are. I didn't mean for this to happen."

"What did you mean, then?"

"I'm not sure," Merlin said. "I didn't think-"

"Now there's a surprise," Arthur grumbled.

"I didn't think I could do this," Merlin finished, still picking at the tear in his jacket.

"What do you mean you didn't think-" Arthur looked at Merlin with narrowed eyes. "Just how powerful are you?"

Merlin's hand stilled at last and he glanced up at Arthur briefly before looking away again. His silence and the flush that was beginning to creep across his cheekbones said more than any words could. Arthur sighed and closed his eyes, rubbing the bridge of his nose in frustration.

Eventually Merlin spoke again. "I thought something seemed strange today in the woods," he said quietly. "But I wasn't sure what it was until I saw the sorcerer. Then I knew I had to get you out of there."

"So you… moved us?" Arthur said, the words sounding impossible to his ears even though he knew it had happened.

"All I wanted was to get you somewhere safe," Merlin replied. "I didn't even think about what I was doing, I just reacted. And then, suddenly, we were here."

Arthur turned his head and saw that Merlin was watching him. "I can tell you what you did," he said evenly. "You knocked me to the ground and your eyes turned gold."

Merlin winced.

"When did you start studying magic?" Arthur asked. "Was it before or after you came to Camelot?"

"I was born like this," Merlin said. "I can't help it, any more than you can help being a prince."

Although Arthur frowned at that, he found it impossible to doubt Merlin's words. Something of his burgeoning trust in Merlin must have shown on Arthur's face, because Merlin suddenly leaned closer, looking hopeful for the first time.

"I've never used magic to harm you," he said earnestly. "And I never would. Every spell I've cast in Camelot, everything I've done, has only been to help you, Arthur. I would only use my magic to serve you, I swear."

Arthur stared at Merlin in disbelief. "Don't you have any sense of self-preservation?"

"What do you mean?" Merlin asked, looking puzzled.

"You shouldn't go around telling people that," Arthur said. "Think of what your magic could do in the wrong hands. People – kingdoms – would use you for their own purposes, for selfish reasons." The very thought of it made him feel angry on Merlin's behalf. "You would be turned into a weapon by those in power."

One corner of Merlin's mouth quirked up in a half-smile. "But you would never do that," he said. "I know you wouldn't. You're going to be a great king someday. And I-" Merlin faltered for a moment. "I want to be there to help you. Only you."

"Then why didn't you tell me?" Arthur asked, and he couldn't keep his voice from sounding hurt. "Why did you keep it from me all this time?"

The smile vanished from Merlin's face. "I know what the laws are in Camelot," he said. "I wouldn't ask you to break them for me, or to disobey your father. That's why I'll understand. Whatever you decide to do with me, I'll understand." He said this with a degree of conviction and bravery that should have surprised Arthur, but didn't.

Later, Arthur would insist that he really had considered every option. But what he never admitted was that, in his mind, there had only ever been one solution.

"Well," he said at last. "I suppose I'll have to keep you."

"You – what?" Merlin looked at him in confusion. Clearly he had been expecting a different answer. "You're not going to tell the king? You're not going to have me executed, or imprisoned, or exiled?" His expression grew more and more incredulous the longer Arthur remained silent. "You're not even going to sack me?"

"Why would I?" Arthur said, trying to sound unconcerned and not as if he'd just committed treason for the sake of his manservant. "It's best that I keep a dangerous sorcerer like you close by, so I can keep an eye on you at all times. Besides, I wouldn't want you running off to another kingdom and promising to help one of their princes."

A slow smile spread across Merlin's face and there was something in his eyes – gratitude, yes, and trust, and something else that Arthur couldn't quite place. "As if I'd do that," he said.

"As if I'd let you," Arthur countered, a response which, strangely enough, only made Merlin's smile grow.

"So," Arthur said, standing and offering Merlin a hand up. "We've already established that you have no idea where you sent us. Do you think you can get us back home?"

"Yeah," Merlin said, shrugging on his jacket and slinging his satchel over his shoulder. "I thought about it before, while you were gone, and I think I've got it all worked out now."

"Get on with it, then," Arthur said imperiously, though he spared Merlin a smile. "And make sure you don't send us somewhere ridiculous, Merlin. I don't want to find myself on one of the towers. Or worse, in the middle of the court."

"Yes, sire," Merlin said, grinning. He clasped Arthur's shoulder, and Arthur clasped Merlin's, and in a sudden flash of gold, they were gone.