Warnings: Spoilers for Series 4, episode 13. Known character death, just not Merlin or Arthur. AU. Takes place during Series 4 episode 13 when Merlin confronts Agravaine. The dialogue is straight from the episode (written by Julian Jones).
Characters: Merlin, Arthur, Agravaine
Disclaimer: I do not own the BBC version of Merlin; They and Shine do. I am very respectfully borrowing them with no intent to profit. No copyright infringement is intended.

Merlin had been gone too long.

It didn't matter that Gwen was giving Arthur looks of concern or that Tristan frowned whenever he started to turn back towards Merlin's last route. The idiot had been gone too long.

No matter what the fool said, Merlin could get lost so easily in the caves. He'd rabbited on and on about playing in them as a child, knowing all the best routes, where there was solid ground and where shafts of ancient mining tunnels could swallow a man whole. And while he'd been babbling about it, he led them deeper into the caves, insisting that he knew what he was doing - a claim that turned out to be not so much true as bravado. They'd had to retrace their path several times. But then the noise of pursuit grew closer. At least five men and Agravaine giving orders and Arthur knew with himself and Isolde both injured, a fight might not go their way; they might all lose their lives.

There was no option but to run.

Before he could urge them on, though, Merlin turned toward Arthur, insisted that he would lead Agravaine's men deeper into the caves, get them lost. That it would be easy.

Arthur knew Merlin was rubbish with a sword but his hand-to-hand skills were even worse. The man could trip over his own shadow and Arthur had seen him do it more times that he could count. Why Merlin thought he could divert Agravaine away from the rest of the group and not get hurt was a mystery but Arthur's agreement on it, letting him go back, was just insanity.

Of course, Arthur could tell himself that he was distracted; after all, Camelot had fallen, he had no idea where his knights were or even if he had knights anymore. They could all be dead by now and this journey of theirs through a darkened cave complete folly.

Still he agreed to it. He had little choice, had hardly protested at all. He should have known better, they both should have known better.

Now, Merlin was gone too long and Arthur would be damned if he'd wait another minute, not with the darkness crowding in.

Shoving past Tristan, snarling out something about going back for Merlin and how they should keep moving, he didn't even wait to hear the replies. The thought of Merlin lying dead somewhere in the shadows only worried him more, making him hurry down the passageway.

Of course, he had a better sense of direction than Merlin. He hadn't grown up playing in the caves, but Arthur could track better than anyone and it wasn't long before he could hear Agravaine asking where Arthur was and Merlin's voice answering.

The bloody fool had gotten caught.

Cursing Merlin's ineptitude and vowing to make the man muck out his stables for a year if they both came out of this alive, Arthur crept quietly toward the sounds. He knew that he'd only have one chance to take them by surprise and rescue his idiot before everything went to hell.

But he was already too late. There was a loud boom, air suddenly displaced and the sound of men flying through the air, horror scouring out their throats as they rose up and then, as the bodies hit unyielding rock, a final silence.

For a moment, Arthur couldn't move. He'd seen it before, seen men thrown like ragdolls, dying as bones broke and blood burst free to mix with earth and stone and mud. It was magic, it had to be.

Gods above, Agravaine had a sorcerer with him. And who else could it be but Morgana? Who else had that kind of power?

But it didn't make sense. Morgana and Agravaine were working together and she wouldn't attack him, not now. He'd seen them in Camelot at the head of the army that had overthrown the citadel. Unless Morgana had turned on his uncle as she'd turned on Arthur? But if that were the case, how had she found them and why would she have left Camelot to kill Agravaine in some dank cave? It would have been better to wait and use him like some black spider, sucking out every last shred of decency and familial devotion before murdering him.

It didn't make sense.

In the end, it didn't matter though. Arthur couldn't stand up to Morgana's power and Merlin was still there, somewhere just out of view. He'd have to rescue him somehow, all without alerting Morgana and getting them both killed. No easy feat.

As he went through the possibilities, there was another sound. His uncle, one hand flung out, was not dead, was slowly turning over, stumbling up to face whoever had attacked him.

"You have magic." Agravaine's voice held astonishment but that didn't add up. Surely he knew Morgana was a sorceress. Surely he….

And then Arthur's heart stopped beating.

"I was born with it."

Merlin. Merlin was speaking, his clumsy fool, his best friend, the one he trusted above all the others and had for so long. The one he told all his secrets to, the one… no, it couldn't be.

As Arthur tried to come to grips with this, to wrap his head around something so unbelievable that he couldn't even begin to understand it, Agravaine backed up a bit, shaking his head.

"So it's you. You're Emrys."

For a moment, Arthur couldn't breathe, waiting to see if his mind was playing tricks on him, that it wasn't Merlin after all but some other sorcerer who just sounded like him, someone named Emrys and not his fool of a servant. After all, Arthur had never really heard Merlin so determined, so… powerful. Most of the time he was an idiot and whining about how much work he had to do or babbling on about how the cook had made his favourite dessert or some other such rubbish that Arthur rarely paid attention to. He certainly could not be here, standing up to Agravaine like an equal.

"That is what the Druids call me."

There was dread in that voice and determination, almost a resignation of sorts; it sounded so much like Merlin that Arthur was beginning to think that it was him.

And if that were the case, he hadn't really known Merlin at all. Instead of a bumbling idiot, he was a sorcerer, defying the laws of Camelot with impunity, an enemy hiding behind bright smiles and nonsense. For years, Arthur had been the one who was the fool.

He didn't want to believe it. He'd had his heart broken so many times, been lied to so many times with Morgana, Agravaine, even Gwen. And now if that man on the other side of the cave was Merlin, he didn't know how he'd survive it.

"And you've been at court all this time. At Arthur's side." Agravaine was laughing, shaking his head, looking at the sorcerer with a kind of respect. "How you've managed to deceive him." He stepped forward, gesturing toward the other man. "I am impressed, Merlin. Perhaps we're more alike than you think."


For a moment, Arthur was numb, and when the denial didn't come, when Merlin didn't say that he'd never deceived Arthur like that, didn't say that he was nothing like Agravaine, cold fury swept through him, scouring him clean.

Merlin, it was Merlin all along. He might have helped rid Arthur of Morgana, helped with the undead army and all the other strange occurrences that had come to Camelot over the years but he had to be playing a long game. How easily he'd tricked Arthur and all the while, Merlin had been turning him into a puppet, slowly, slowly, so slowly that no one had an inkling of what was going on.

Arthur was the one who was the idiot. Trusting those around him, thinking that they had served him and loved him with open hearts, instead he'd been played, had been used for their own gains.

He didn't need to hear more. Brushing at his face wet with dew or water dripping from the ceiling, certainly not grief streaking his cheeks, he turned, quietly walked away.

Far behind him, he could hear the sound of a body falling, the silence that death brings. And then footsteps coming closer, Merlin's footsteps.

Arthur knew he'd have to play a long game, too. No more would he trust those around him. No more would he accept the lies that came so easily. No more would he be the simple-minded fool.

Merlin had taught him something he'd not soon forget. A king was ever alone; he couldn't afford to let love into a heart that would only be broken with lies and manipulation, would only be destroyed with bright smiles and shared laughter.

And one day, Arthur would teach Merlin just how painful betrayal could be.

The end.